upgrading hardwares is more like the "easy way out" for some people. I said some because even with the latest and best hardwares, people are still having problems. at the same time, upgrading from 512MB to 1GB of RAM has improved gameplay for many. It has been suggested that there are serious memory leaks within the game so having a large amount of RAM wont necessarily solve your problems.
Another easy way out is upgrading your video card, I upgraded from an GF FX5200 (2.5 yrs old) to a GF 6600, while I have noticed much better performance, I still get CTDs, though less frequent.
Basically what I'm trying to say is, at this point, with this current release, there are many issues that's causing the game to "demand" higher-end hardwares. I'm sure after a few patches or so, with the game being more "stream-lined", people who meet the minimum requirements (or at least the recommended) will be able to play the game and enjoy it. face it, a lot of people who bought the game are already playing and enjoying it. and I'm sure not all of the have the latest and best hardwares. So my advice would be to wait before spending more money on new hardwares. I did only because I havent done so since I built my system 2+ yrs ago and had some money left over from summer.
EDIT: wanted to mention that unless you know what your problems are, you shouldnt upgrade. Prior to the upgrades, I wasnt getting any "black terrains" or any errors. It was just slow. Upgrading will most likely NOT solve any of the serious problems. It will most likely cause you even more fruastrations.