Of course the 7800GS is the fastest.......it does have the highest number
But seriously though, I had the 6800nu unlocked/overclocked and the 7800GS is a lot faster. my 6800 died and I needed a new AGP card so I got the eVGA 7800GS CO and it is a good card. Quite and single slot. I run BF2 with everything turned up @ 1280x1024 4xAA 16xAF and it runs fine. Of course people will say go PCIe and if I were upgrading now I would too but you're the only one to know if you want to go PCIe, I havent yet and I'm doing fine but give me a couple months and I am for sure.