I'd suggest a 9700NP for ~$215, or a 9500P for ~$180. The former has twice the memory bandwidth of the latter, which will make it much faster at high resolutions with AA&/AF. Get the 9700NP if you can go $15 over-budget, it will be faster and last longer for a small price premium.
(OTOH, I think the 9600 series may have some optimizations for double-sided stencils that the 9700 doesn't have; I'm not sure if those optimizations will make the 9600P competitive and possibly faster than a 9700. You really won't know until iD releases a D3 benchmark; I'm not sure the D3 alpha will be valid to see those optimizations, but I haven't seen 9600P benches on it yet, so I can't say for sure. Regardless, the 9700 should be faster on all other games, due to its far greater fillrate and memory bandwidth.)