Yes that card will deliver dual screen graphics easily (I ran a GTX460 (lesser card) dual screen every day). With Nvidia's 3D vision you can run 3D with an applicable monitor. Any card in that price range will be fine (6850, 6950, 550Ti etc.. + the new gen)
NOTE: you can not game over 2 screens with vista or 7, the drivers do not support it anymore. you either need 3 screens with a capable card or xp, but that will only play older games lik3 L4D2 over 2 screens.