Hey, just a tip for you from me. I have a computer decked out with stuff and a 360...still middle-class and not upper-class by the way...Keep your 360 for now. For the time being, 4gb of RAM will hardly show up on anygame (most people here are indeed gamers, so that's all anyone cares about)you play over 2bg of RAM. Although...I built my rig with a few "server-style" parts and I have 8gb, I know what it's like. Just get a good processor and a decent video card (if you can deal with it, go with a 768 and not two smaller ones...my personal opinion there) and use 2gb of RAM.

Additionally...If you use Windows Vista Ultimate (or anything except basic) just set the visual properties to the Vista Basic and it does wonders for your PC, even though it may not look the absolute best you can get, it's still nice. If you are just using Windows XP...there's really no need to go to 4gb.