Nothing between 7600 GT and 8800 GTS makes sense.
I just ordered an ATI X1650 XT card myself -- it's in the same price class as the 7600GT, but seems to edge it out in the majority of the benchmarks.
(One of the main differences is that the X1650XT has 24
pixel pipelines, vs. 12 for the 7600GT. the other specs are fairly similar)