Personally, I'm for NV-based cards..
Mainly due to, as Husk already mentioned, the Linux support is far superior then ATIs. Shame, that a company like ATI can't get their shit together and realize that Linux is a hot ticket right now. *Shrug*
As for a video cards in general, I'm going to say they all suck. This "kicking each other in the balls" game they are play down right sucks. I say a card that supports all OSes, all GFX APIs with decent frame rates will be teh win.
I miss 3Dfx at times.
Furthermore, if ya must know.. I'm using a NV 5700 (256meg) card.