I had a 6800 Ultra before - it was a review sample on "permanent loan" from a friend and I thought it was about time I returned it in fully working condition! Great card but the cooler noise to used to piss me off - even at 25% speed it had this horrible grinding quality.
The 7600GT is pretty much as fast and completely silent. I suspect there is a lot of overclocking headroom too. Couldn't say no for £115 - what a bargain!