I just recently purchased a 9800gtx+. It was on sale at FS for $169. I'm pretty sure I'll be returning it though. Even with price being an issue, you are better of to sell your 8800gt for +$100 and put that money towards a GTX 260. With a newer refresh of the series coming out soon, the prices of the existing 260's should drop.
That is what I'll be waiting for.
Of course if you are gaming at less than 1680x1050 then the 9800gtx+ is fine. The 260 really shows improvements at 1920x1200.
I agree with fellows while pricing looks very attractive right now for nVidia newer 9 series they don't offer the significant performance improvements you might be see going from an 8800GT to a GTX260. Give it time let the pricedrop and MIRs continue and in no time you'll be able to get a GTX260 for pretty much around the same price of the 9800GTX+