yeah i'd go with the 7600 as well. but if you'd be willing to, get the 790 0GT, it recently came in stock and is about $180 more, i no its asking a lot but, it will last you for a long time, and will be able to run Half Life 2, battlefield 2, COD2, Americans and all those are games, Smoothly on highest settings, but i cant say the same about either of the other cards you suggested.
as for capture card, go with a Hauppauge.