For the record, I'm sure everyone has different needs, and I'm probably going to forget things, and I'm working off of my experience in 2010, so things may be different. But I know that right before I was getting ready to leave for BMT, I was having a really hard time finding a list of what to bring, and since I had no idea what to expect, I was really concerned about what to pack to make sure I had everything I needed, but didn't bring anything to draw extra MTI attention.
As far as how much luggage to bring, I would recommend packing two bags: one very plain black backpack to bring with you to Basic, and an actual suitcase with civilian clothes, electronics, and anything you think you might want while at tech school, and ask your parents/significant other/friend to bring it to you at graduation. Just leave space in the suitcase for your backpack. If no one can come to your graduation, that's fine; they have a storage closet in the dorm for suitcases. It's just easier and more convenient to bring as little as possible, especially since you won't need any of it until you leave, and because as soon as you get there, your MTI will have you dump every item you brought onto your bed to be checked for contraband. Keep that in mind.
For what to actually bring, first of all, if you get on the plane and realize you forgot something, don't sweat it too much. One of your first pieces of business when you get to Lackland will be to go to the nearest shoppette, which sells pretty much anything you could possibly need. I would recommend packing a toothbrush and toothpaste for the trip there and for the first night, but for pretty much any other toiletries, it's probably easier to just wait and buy them there. You'll also be given a debit card with a few hundred dollars (out of your first paycheck), so while you can keep money on you if you want, it's really not necessary as long as you budget even a little. And since you can't buy food or anything but essentials during your shoppette trips, it shouldn't be hard.
Here is another decent list of what to bring, which also links to the "official list," though they also say to forget about the official list. I disagree with him in a few places, mostly about things like toiletries and phone cards, but ultimately you'll end up being fine either way. It doesn't say when this list was published, so I think mine might be more up-to-date, but not sure. By the way, this guy's articles on About.com have good answers for pretty much any question you have about the military.
Okay, on to my lists of what to bring and not to bring.
-3-4 plain t-shirts (You'll only need them for the trip there and the first two or three days, until your uniforms are issued)
-2-3 pairs of jeans (Same as above, you won't be able to wash your clothes every day, but there's no one there to impress, and the less things you bring, especially bulky things like jeans, the easier. Especially since you want everything to fit back in your backpack for storage)
-Pair of good quality, plain-looking running shoes (Mr. Powers disagrees, but I think mine's more current. We had the option to buy running shoes there, and they're Asics, so they're good quality, but they only have the one style. And we were also allowed to use ones we brought, as long as they weren't brightly colored. You're going to be doing a lot of running, so I liked being able to pick my shoes. It is physically impossible to find plain white running shoes, so just get the least colorful ones you can find. Even the ones they sell at Basic have blue or pink on them. Also, you can just wear them there, so one less thing to pack)
-6 pairs of white running socks
-1-2 bras (You'll only be wearing these on the way there and maybe during graduation)
-4-6 good sports bras (You'll pretty much be living in these
-6-8 pairs of non-flamboyant underwear (Mr. Powers says you'll have to buy some, but we were not required to)
-3-5 pairs of black Spandex shorts (You'll be wearing these all the time too; wear them during PT to keep your shorts from riding up, and under your ABUs during the day to keep your pants from chafing from all the marching. These are also good to sleep in, instead of PJs; jump out if bed and your halfway dressed)
-1 towel (I think you only need this for the first couple of days; after that they give you some)
-Toiletries: shampoo, conditioner, toothpaste/toothbrush, etc. (I would recommend if you bring these, to just bring small sample sizes, especially since if you only bring a backpack, you won't be able to carry large bottles on the plane. You can buy all of them when you get there, and your MTI
will probably give you pointers on what to buy; my pointer is to get a
pack of those acne wet face wipes, because they're great to helping you
actually feel clean between showers after days of marching in the Texas
sun. Also, unless you're actually on your period when you leave, don't bother bringing pads or tampons. You can buy them when you get there, and a lot of girls stop having their periods completely while they're there, just due to the stress)
-Lots of hair bands and bobby pins that match your hair color (The Air Force doesn't require you to cut your hair like the other services do. However, if your hair goes past your collar, you will have to have it up in a very severe bun at all times. I went in with pretty long, thick hair, and I pretty much slept with my bun in so I didn't have to redo it every morning, but it frequently hurt, damaged my hair, and I still got yelled at [by other TIs] because my hair was so thick, my bun was almost to big to be in regs [it can't extend more than 3 inches]. About halfway through, we were allowed to go to the base salon, where I and about a third of my flight got our hair cut short. My hair frizzed up horribly, since I couldn't blow dry it, but it was infinitely more comfortable. A lot of girls get through basic with their hair intact, but this is just something to think about, especially so you can decide if you want to have your hair professionally cut, and not by someone with 20 other girls in line. If you do cut it, I recommend cutting it pretty short--ears or shorter--so that no one can ask if maybe your hair is too short. Your TI might know it's fine, but you have to deal with all the other ones lurking about, too)
-Paperworks (College transcripts, driver's license, if you have a marriage license or dependent birth certificate, social security card, enlistment contract, banking information, prescriptions)
-Glasses, if you wear them
-Cell phone and charger (You will get to make calls home, usually on Sundays and if you do something good. You might read that you should bring phone cards; there are pay phones, but we were always allowed to use our cell phones, which were much more convenient; I haven't heard of anyone who's gone through after me who couldn't use their cell, but if that rule has changed, you can always buy one)
-List of personal contacts, with current phone numbers and addresses (Especially if you're trying for an Intel field or something that needs a security clearance; they need a non-relative contact for every place you've lived. And do not trust your recruiter to do this for you.)
-Black pen (You're going to be signing a lot of stuff. Just go ahead and put one in your pocket)
-Paper, envelopes, and stamps; maybe pre-address and stamp some to your favorite people
-Pictures, a Bible, or other small mementos (Mr. Powers says to be careful with these, as the TIs could make fun of them. I didn't have a problem, but it is something to take into consideration. Any pictures anyone mails to you will also have to be shown to your TI, but I guess at least it wouldn't be on the first day, and in front of any higher-ranking TIs who may show up to mess with the newbies)
-Cheap waterproof watch (Not necessary, but very convenient; I say waterproof so you can wear it in the shower, or in the mud, or the sand, or whatever crazy situation you find yourself in. However, it will inevitably come out a bit worse for wear, so definitely don't invest a lot of money into one)
-Minimal make-up (If you really want, though you can only wear a very little bit and only during graduation, and they do have make-up at the shoppette. I would recommend not bringing any)
Not to Bring:
-High heels or flamboyant clothes (This happened in my flight, and she got immediate attention that first day, and not the good kind)
-Contact lenses (You can technically wear them for the first couple days, but you'll be very sleep-deprived and in Texas heat, so they'll be very uncomfortable, and you're not allowed to wear them at all once they issue you new glasses, which will happen within a few days. Put them in your Tech School suitcase. Mr. Powers says you can't wear them at all. I honestly don't remember if I wasn't allowed, or I just didn't because they hurt; either way, don't bother)
-Pajamas (Like I said above, you don't need them; we all just wore our Spandex shorts and PT shirts to bed)
-Hair implements (Maybe get a super portable version of your hair dryer, straightener, whatever, but you can only use it during graduation, odds are someone else in your flight will bring one and let you use it, and if they don't and you're that desperate, they sell them at the shoppette)
-Jewelry (Any jewelry that isn't a sports watch or a wedding ring--engagement ring doesn't count--will be required to be locked away. Just don't worry with it. You are allowed to wear diamond or pearl stud earrings during graduation, but again, you can buy them there)
-Pretty much anything valuable, including all your electronics (Put those things in the big Tech School suitcase; you won't need them at Basic, though if you're phone doesn't do music, maybe bring your iPod for the plane/bus and slip it in your backpack)
-PT: push-ups, sit-ups, running (This one isn't necessary, but it does make your life there a lot easier; I did almost no exercising before I left, and the program is designed to help out-of-shape people like me to get up to standards within the 8-week time, and while it worked, I would have struggled a lot less had I worked out more ahead of time)
-Learn stuff (This one is only for if you're feeling nervous and really want to get that head start, because BMT is completely designed to help civilians who know absolutely nothing about the military to become Airmen. Absolutely everything you need, they give you. But, if you really want to feel prepared, you can start studying the Air Force ranks and insignias. You'll also have to learn your chain of command, but part of that is dependent on what squadron you're assigned to, so can't really study it. If you're looking for more light reading, here's another good article on About.com that goes through what to expect week by week. Again, some of it, like the phone situation, is a little out-of-date, but most of it's still really good information)
-Read Ender's Game by Orson Scott Card (This sci-fi novel has actually been one of my favorite books for years, so imagine my surprise when I heard it was on the Marines' recommended reading list. The Air Force doesn't have it on theirs, but I found it really helpful while I was there; mostly it just helped give me an understanding of the reasoning behind some of the seemingly crazy things my MTIs were doing. For instance, it helped me realize that when my TI was yelling at me, he wasn't mad at me. He just knew that odds were 45 other women were probably making the exact same mistake, so rather that calmly teaching the same thing 46 times and having it be disregarded as unimportant, they can yell really loud at one person, then everyone learns it and registers it as a big deal, or else they wouldn't be yelling about it. It's all just mind games)
-Practice the phrase "Sir/ma'am, Trainee [last name] reports as ordered"(You will be required to say this before saying anything to any TI, unless all you're saying is "yes" or "no." [As in, "What's your favorite ice cream?" "Sir, Trainee Skywalker reports as ordered. Chocolate." This one is especially hard to get the hang of, and you will no doubt get yelled at a lot for it, but the more you practice, the better off you'll be)
-Don't leave getting ready until the last minute (You're about to start a completely new life in a new place, on your own. Make sure that you know where all your important documents are. As for all your stuff, you will be able to do one "home of record" move, where the military to pay to ship your stuff from your parents' home, your apartment, a storage unit, etc. But when that happens, especially if you were living at home, it'll go a lot smoother for you and whoever will be helping you out back home if you've already put all your stuff together. They'll pack everything for you, but at least figure out what you want to bring or not bring, and anything you don't want the movers to see, go ahead and put in a closed box and mark it. When you're doing this, also keep in mind while you're deciding what to bring that if you're not married or have a kid, you'll probably be living in the forms for a while.
-Don't freak out. If you met all the recruitment qualifications, then you'll be able to make it through basic. That's what it's designed for. You can make it. You're going to be nervous and confused for the first week or so, but once you get into the routine, it may be one of the simplest times of your life. You are getting paid to exercise, study, eat, and sleep. If you've lived in the real world at all, you know how nice it would be for your biggest worry to be how many push-ups you can do and whether a colonel wears an oak leaf or an eagle. To not make it through on time, you have to fail pretty catastrophically, which mostly only happens if someone gets severely injured, or is just lazy, and even then they mostly only get delayed by a few weeks. And then you're off to be paid to receive training for a guaranteed job that you can keep for however long you want, with full benefits and money for housing. And if you do decide to get out, you just got paid to learn a marketable skill. Yes, there are hardships and sacrifices, but it's still a pretty sweet deal all around.
But mostly, you CAN make it through basic training.