Macintosh and OS X ftw!
My current Mac is an Intel Core Duo iMac with 2Gb Ram, 250Gb HD, Radeon X1600. The first generation of Intel iMacs.
I used this iMac (running Windows/Bootcamp) to play City of Heros/City of Villains for a whole year until I upgraded my PC. Worked great!
Got my PC all nice and upgraded, and XP back on (HATED Vista! Slow Resource Hog...be gone forever!) it and it's a pure game machine.
Use Macs at work (production artist at newspaper).
Now toying with an Amiga 1200HD

-Mark