ATI makes the fastest gaming engine...for now. As far as nvidia having a wide selection of cards, so does ATI.
Radeon 9800Pro, 9700Pro, 9700, 9600Pro, 9500Pro, 9100, 9000, 8500, 7500, 7000, its All-in-Wonder cards, and its FireGL cards.
The main difference is the ATI has the only the fastest gaming card...thats it. nVidia on the other hand makes hella fast gaming cards, and the fastest rendering cards on earth. The QuadroFX will eat ATI's FireGL alive. www.tomshardware.com
nVidia makes motherboard chipsets that I've noticed alot of yall have. The GeForce FX might not be quite as fast as the 9700Pro and the 9800Pro, but it has technology built in it that ATi cant touch. nVidia is the biggest GPU manufacturer in the world. its part of the NasDaq. nVidia is a bigger company than Dell. ATI makes good stuff, i wont front, but they are out of their league when it comes to nVidia!