ATI video + Intel CPU = Fucking Win.
Seriously though, the card all depends on what you want. I have to admit though, ATI's Linux Drivers are a bit unreliable, whereas the Nvidia GfX cards are well-supported.
Your CPU choice, however, is dissapointing. I'd go with the Intel, and, from what i've seen, the Most Capable ones are the Intel Xeon Quad-Cores. The Comp I use at work has one, and It's a Monster.
I never really liked AMD processors because the Only ones that seem to be worth a shit are the 64-bit ones...
and 64-bit = Instant fail...