Re: NVDIA or ATI (over Linux)
Not sure who told you that. AMD has recently opened the source code to the community so I'm sure they will improve..but I've lost sleep over trying to get an ATI card installed.
Nvidia on the other hand, while there are bugs, I have had 99% all around great experiences with.
Cards used were 6800GT, 7800GT, 7900GTX, 8800GTS both vanilla and SSC edition. Haven't run my 9800GTX through the mill yet, but I'm sure it will be fine.
Also this Nvidia linux forum is linked off of Nvidia's site with actual nvidia employees here daily answering questions and squashing bugs.
I don't believe AMD even has such a forum...could be wrong though.