My best Windows box is on the edge of obsolete now. I am able to run games like Doom 3, Quake 4, UT2004, Halo...etc on high settings with my Radeo X800XL. I can run Battlefield 2 at higher settings, but not TOP. My best #DMark03=11127
AMD Athlon XP 2500+ (2.5GHz@400FSB)
Epox 8RDA3+ Pro
1GB Cosair XMS PC3200 in dual channel (3-3-3-8)
Ati Radeon X800XL (431,526)
Like I said, I'm on the edge of obsolete as far as games newer than Battlefield 2.
How tough is your vid card?
What are you going to buy for your next video upgrade?