Win 64 and gaming

Forgive the noob here, but I'm building a new rig, and my buddy is buying mine. So he is geting my copy of Windows XP Home. I have a copy of 64bit windows here, and I do not want to spend money on windows until I get back to school, where I can get it for like 15$. Now would I be able to play my games (Oblivion, Fable, NFS:MW, Fifa 06, NHL 05) on that OS with no problems, assuming I have the 64bit drivers for whatever Nvidia or ATI card I get?

That's pretty much it. I've only had issues with three things in XP x64 - no drivers for my HOTAS, ODBC connections (drivers for MySQL & PostgreSQL, keeping system DSNs past reboots, and remembering where the 32 bit ODBC manager is), and using 32-bit shell extensions (requires firing up a separate 32-bit Explorer process to handle them). Even at work we've only hit a few snags with virus scanners, system management utilities, and some odd behavior when setting up AD replication between Server 2003 IA32 and Server 2003 x64.

I didnt have any problems running any games in X64 when i Ran it for a while.

Go MSDNAA. I can't install my winxp until i go back to school as i forgot my key. I still have my 2000 key though, so at least I have something in the mean time.

You shouldn't run into too many issues but expect them, as its not always stable, at least it wasn't for me. Steam apps work though, so if you ever get into them...