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. Feel free to pick and choose what sounds good to you and ignore the rest.
1) Money. South Africa is an expensive country, quite a bit more than the average Peace Corps country. It's quite possible to make it on the 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, at least on vacation—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 so desire. 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 hard drive death 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 quite as critical as cell phones are a bit closer in price to the US.
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, and to run such a device, you'll need a converter that can step down the voltage. Those tend to be rather expensive. If you're worried about power surges, you can bring a surge protector, or buy one here; they aren't too expensive.
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. If that sounds like you, go with the best backpacking-style stuff you can afford; hauling around heavy tents and sleeping bags on public transport is a terrific nuisance. (Not bringing this stuff was my biggest regret, I had it sent from home.) It doesn't have to be Antarctica-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 looking back I would have bought an ebook reader. Right now I have an Amazon Kindle, and I absolutely love it. I take it everywhere, the battery lasts forever, and the screen is very easy on the eyes. It's not necessary to buy dozens of books off Amazon; you can thousands from Project Gutenberg and elsewhere. However, it is worth poking around the Amazon site for cheap or free books, there are some hidden gems there. I've downloaded loads for $5 or less.
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 into the Peace Corps administration. Pressed pants or dresses, 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. Also don't forget that it gets really cold during the winter, and there's usually no indoor heating. I'd bring enough warm stuff for -5 C (23 F), which might be a bit of overkill, but better than being cold.
6) Take it easy. Something about the way Peace Corps works in South Africa often makes for a rather abrasive environment, particularly at PST. It's anybody's guess why, but I'd just say be ready to deal with a lot of logistical screwups within the Peace Corps bureaucracy. It can be a huge pain in the ass, particularly with the deep South African tradition of buck-passing, but I think the critical thing to realize is that it doesn't have to ruin things for you. PST very well might provide you with enough material to complain every waking moment, but it should also be fun! You make new friends, you learn a new language, and some (hopefully) nice people take you into their home and make you part of the family. Before they kicked me out of the last PST, I said it's good to develop a "Zen mode," where you don't let things you can't control ruin your afternoon. It doesn't always work, but it's good to try and head things off before you have to adjust your blood pressure medication.
7) Sexual frustration. Most volunteers are young and many are single, and there will likely be a large gender imbalance towards females. This sometimes 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.Anything I'm forgetting?
-Bring a nice pocketknife with a wine opener.
-Smartwool socks are extremely nice, especially in the winter.
-Bring a decent backpack if you're into hiking or backpacking.
-Playing cards or some travel board games are always a good idea.