Hi Dennis,
I was facing the same question over the Summer. The only difference we were giving from our sales, was the 7600 is a NEBS compliant and is treated as a router. I find that there are more options available from a switching point of view with the 6500 series that still aren't available for the 7600.
If you are looking for more of a solution to connected workstations and other networking devices (switches, SANs, etc), I would select the 6500. It use the same supervisor, so you still get the same routing performance.
We selected the 7600 with a bunch of 2950's, and looking back it lately, I would have done it differently.
Hope that helps.
-- Dominique