The video card isn't available yet so run off the on board GPU until you're able to get it. But the 640 is definitely better than entry level Radeons at that price range. The Geforce GTX 640 is definitely better than the onboard HD3000 of the i3-2120 and will last a lot longer. The card is equivalent to a Radeon HD 5770 / 6770.
Ahh, thanks for the advice so far; you guys are taking me in a radically different direction than I planned (discrete vs integrated graphics), but it's a good one.
One other quick question though... My mother has a lady-boner for MS Office 2010 Pro. Any ideas on how to get it for cheap? OEM version or something? Of course this wouldn't be included towards the $600 computer price.