HAHA! $1,000 will probably get you 1/4th of a fully loaded Alienware computer.
Anyways, build a custom computer. It's fun and rewarding, not to mention the satisfaction you get when you see everything running fine. Or if you're not the DIY type, buy a cheap one from iBuyPower or Monarch Computers.
umm i wish the person could tell us what type of games he is going to run on this comp, then we could suggest somethign with a 1,000 dollar budget. sh*t a 1,000 dollar budget for a gaming computer...
Look for those as your base specs - that would be an amazing computer. Get a Core 2 Duo definitely, and that motherboard is very good. You want 1GB of RAM at least, and that graphics card is a minimum.