You want at least a 1 gig video card, I recommended a GTX Nvidia series, SLI for 2 to get the most. Processor i recommend nothing less than an intel i5 but shoot for an i7. Also shoot for more than 4 gigs of ram minmum with windows 7 prof (home is ok if you must) 64bit, do not get 32 bit!!!!!!!
I run a quadcore i7 2.6ghz with (2) 1.8meg video cards (GTX 275) for a total of 3.6 megs of video, and 6gigs of ram and I run WoW with max settings and average 60-100 FPS
Been playing WoW since Beta