[q=Samuraid]The X1300 pro is OK, but not exceptionally fast at all. A 7600GT is a much better choice.[/q]
Personally, I wouldn't go ATI at all. We'll have to see how they perform after pairing up with AMD, but for now I'd buy a nVidia. Crossfire is generally less supported than SLI, especially under Linux compositors, so that's a big factor for me.
[q=Yamaneko]Yeah, that extra 128MB of GDDR3 is helping a lot I'm guessing. Is that an Athlon XP or 64?

EDIT: Does your custom title give the answer? [/q]
Yep.
[q=MecaKane]Speaking of Oblivion, AMD 3200+ run it well? Also is this the graphics card you're talking about? It doesn't gave GDDR, if that's terribly important.
I'm getting a new computer in the next couple of months and I really, really want to be able to play oblivion.[/q]
A 3200+ will run Oblivion very smoothly at a res of 640x480, pretty smoothly at 1024x768 and smoothly enough at 1280x1024.
There are quite a few different models of 6600GT; you'll find permutations with 128MB or 256MB of GDDR2 or GDDR3, different clock speeds, PCI-e or AGP, etc. The best one you could get would be PCI-e/256MB of GDDR3.