Need a card recommendation

I have a friends old rig and i had a spare cm 212+ kickin around so i tossed it in for him and oc'd his E8400 Core 2 Duo. I know this is a old processor and he is only running 800mhz ddr2 so i can only push his processor so far before i am reaching a limitation from his ram. So far i have managed to get 3.8 stable for him but he wants to put a video cards in it to last him the next year or so. he plays all sorts of games ( rts, fps, mmo ) I know his CPU will be a bottleneck no matter what but my question is what GPU to recommend to him without him having a sever bottleneck. I do no this will depends on the game. I know some games now a days utilize 4 cores and he is going to suffer in those games in the bottleneck region more so then games like sc2 were it only utilizes 2 cores. He is looking in the 100$ - 220$ range for a graphics card. he said he wants to stay nvidia due to borderlands 2 and physics. The best suggestion i can think of right now is the 650 ti which is up coming to be released soon here. I am looking for suggestions for the best card in the price range for the situation at hand. Thanks for any suggestions!!