The Asus 8800 GT T.O.P heads to the top of the charts with its aggressive factory overclock, putting a lot of distance between the other overclocked 8800 GT from BFG. While the XFX 8800 GT 256MB shows that card can still keep without 512MB of memory in some games.
As far as bang-for-buck, the $179 Gigabyte HD 3870 and $209 BFG 8800 GT OC look pretty good -- though that $30 dollars price difference does translate into a big difference in Bioshock.