Something I didn't notice directly mentioned is that Games typically push graphics cards to new levels, not your PC's RAM. That is probably the reason kingofwale said his laptop with 2gb mem can't run new games. He probably has a video card or cpu issue not a ram issue.
Again, I wouldn't worry about your ram for at least a year. Keep in mind I think most of us are assuming you have XP, not Vista, which is a big resource hog.







