Heh, maybe it's just me, but if I had a pretty current PC, I would invest like half of that 2,000. It wouldn't hurt that much if you lost on stocks, since it was free money anyway. Too bad I don't know how to invest on wallstreet, I totally called out google at it's IPO (somewhere below $85) ...then it went up to like $200! Heh, I even said I'd get out once it hit that point, then it dropped back down! Oh well, just part of being young I suppose :P.
You could also invest in bonds or some other sort of... thing. Or just plop it in your savings account and save it for something, well, important.
I'd definately spend some of it though
. Honestly though, I couldn't see spending 1k on a case.... ever. I think you should try to wait for the next generation of video cards actually. You are perfectly set up to get the most use out of it. Usually hardware comes out and you can't afford it til it drops in price... like 3-6 months later. You could buy it right away, that'd be sweet
. Plus, buy some other stuff for your pc or wtv you (he) want(s).