Instead, I'll just give some general advice about what to bring and what to worry about, in more-or-less descending order of importance.
1) Money. South Africa is an expensive country. It's quite possible to make it on the pitiful Peace Corps stipend alone, but I only know of two people offhand who have done it and they're constantly scrimping on everything. Most of you, especially older volunteers, will have access to a bit of US cash. My advice is to be ready to spend some of that--if the volunteers I know are any judge, it's going to be almost impossible to resist. I eat nothing but beans, rice, and Morvite and I still dip into my US funds occasionally. There will be lots of vacation opportunities, and there's no reason why you shouldn't take full advantage of them. Besides, a night at a nice B&B every once in a while can really help your sanity. In my opinion, there's really nothing wrong with living it up a bit if you can afford it. Living on the village standard is an admirable goal, but Peace Corps is primarily up to you, and don't listen to anyone who says different.
2) Electronics. This is sort of related to #1, but it's worth considering on its own. Electronics here, especially computers and related peripherals, are roughly twice as expensive as in the US (cell phones aren't as bad). I recommend bringing along a laptop, and an external hard drive with at least 500 GB of space. Make sure it is USB powered. The power will probably go out a lot where you are, and this will help prevent crashes as the drive can run off your battery. You can load it up with shows and stuff, but usually you can get those at PST if you must. If you know how to get an unlocked, SIM-ready phone in the US (don't ask me), that could be a good buy but it's not as important. Power is 230V and 50 Hz here, similar to Europe. Practically all sophisticated electronics nowadays can take that voltage with only an adapter, which just arranges the conductors so they can get juice from the SA plugs. Look on the transformer of your device, it should say somewhere 100-240V, and 50-60 Hz. Basically all laptop, ipod, kindle, etc. chargers are like that. I've only heard of a couple common devices that need 120V--a Nintendo DS is one, I think. You can get adapters online, just make sure they say SA specifically, as SA has a weird plug scheme that isn't included in a lot of the "universal" adapters. Most people don't bother, and during PST usually they'll order a bunch of adapters for everyone that wants one. That's what I did.
3) Camping gear. Camping can save you loads of money at backpackers and hostels. Go with the best backpacking-style stuff you can afford; hauling around heavy tents and sleeping bags on public transport is a nuisance. (Not bringing this stuff was my biggest regret.) It doesn't have to be Everest-ready or anything (most of South Africa rarely gets below freezing even in July), but the lighter the better. Bring a nice pack towel.
4) Books. I brought a lot of books. I don't really regret it, but I can see someone else needing all that space and weight. On balance, I think an e-book reader would be a good investment if you have the cash. There will always be a lot of books to borrow, and there's a small library at the Peace Corps office in Pretoria. The only drawback here is durability--I've heard from two volunteers whose readers' screens broke. Try and get a tough one.
5) Clothes. I don't have much to offer here, except that South Africans put a lot of stock in dressing nicely, which spills over a lot into the Peace Corps administration. Pressed pants, shined shoes, the works. I wear nothing but Dickies to school so I don't have to iron, so you might want to throw in a pair or two of those if you're lazy like me.
6) Don't listen to PCVs. Ok, I see the irony. But seriously, at PST there will probably be a lot of condescending and sweeping advice. Take it with a grain of salt. Something about being a PCV here tends to make people rather cocky, especially in front of fresh volunteers. In fact, don't take anything at PST too seriously, especially not the preening moralizing you might run across. I thought it was mostly worthless--for me PST was the worst part of the volunteer experience, muggings and all. Just get through it; listen to the people that seem reasonably sane, and if someone is obnoxious, read a book.
7) Sexual frustration. Most volunteers are young and many are single, and there will likely be a large gender imbalance in favor of females. In my experience this often leads to weird competitive phenomena that don't work out for anyone. Combine that with South Africa's titanic HIV epidemic, and you can see how there's a chance one could end up clawing up the walls. Be warned.
-Bring some maps of the US and the world. Even more than one perhaps—they make great presents.
-Bring a nice pocketknife with a wine opener.
-Smartwool socks are supposed to be nice.
-Bring a decent backpack if you're into hiking or backpacking.
-Playing cards or some travel board games are always a good idea.