I use a radeon 9500 pro on my home combustion system. A Nvidia Quadro 3400 at work. I’m buying myself an Nvidia 6600gt for my home system over christmas. I would strongly recommend an Nvidia card regardless of price range.
Honestly, I’ve heard alot about the Quadro cards, but I’ve never seen any percievable performance improvement over a significantly less expensive consumer gaming card. I would recommend just going with an SLI of two top of the line Nvidia gamer cards… I think the 7800 ultras were the most recently released.
However if money is of no object to you, why not buy a Quadro 4000 Dual SDI?