Vista 64 is fine (despite what mac ads tell you), and if you ever think you'll get more than 4GB RAM, it's required. Read up on it here:
http://techreport.com/articles.x/15941/12
Also, check the PC build in my sig :) $489, runs Crysis on high @ 29fps
My only complaints about cyberpower / ibuypower is that they like to push you towards older mobo's (so upgrading is harder) and crappy power supplies. But if you're careful you can get some good deals.