GTS 250.
On a serious note since for some reason Evga or BFG 9800GTX+ are still selling for around $170 on newegg and op is going for the bang/buck the following gpu should be the best choice.
Sapphire HD 4870 512 - $179.99 F/S
A lot faster then 9800gtx+ for $10 more and comes with a non reference cooling design/heatsink.
On a serious note since for some reason Evga or BFG 9800GTX+ are still selling for around $170 on newegg and op is going for the bang/buck the following gpu should be the best choice.
Sapphire HD 4870 512 - $179.99 F/S
A lot faster then 9800gtx+ for $10 more and comes with a non reference cooling design/heatsink.