Despite the large size of the monitor, as far as your graphics horsepower is concerned, it's the same as any other 1920x1080 monitor. Unless you plan on doing any 3D gaming, pretty much any upper-mid range card will do, depending on the games you play.
Basically the three questions you need to answer to let everyone here give much better recommendations are:
1 - Are you planning on doing any 3D gaming?
2 - What games are you playing?
3 - How cranky do you get when your fps falls below 60 on mega-ultra settings? (I have a few friends who get really frustrated when they're "only" getting 50 fps on uber-high settings.)
Core 2 Duo E8400, 4 GB DDR2-6400, 500GB 7200RPM HDD, GTX 460 1GB, 9x 2TB 5400RPM HDDs