Which card goes better with this system?

I am looking to build a new system, and I have yet to decide on the video card. I use 2x Samsung 226BW's at 1650x1080. I am not extremely concerned with having ultra high settings on every game, I don't mind medium of the road settings. I care more about having many applications running at once. The other components I am getting are the Q6600, 4 gig's (2x2), I was thinking the Silencer 610 power, and I suppose my motherboard choice would be dependant on the card I'm getting.

The more I read about the 9000 series, the more it seems likely I should be looking to get either an 8800 GTS (G92) or a 3870X2. I usually build a new computer every 1.5 years or so, and don't usually upgrade between. The games I like to play are: CoD4, WoW, TF2, and when Starcraft 2 comes out, SC2. I just really like to be doing multiple things at once, and using the second monitor for watching movies / tv shows. I was curious if under these conditions the 3870X2 was worth the ~$150 increase.

mmm...


Using dual screen, the 3870x2 should theoretically deliver MUCH MUCH higher performance than using a 8800GTS, because while crossfire doesnt give perfect scaling, using 2 screens ione core for each there is no scaling involved.