Theres a thread on CG talk with reference to problems with Nvidia 8800 drivers and Maya, I guess thats not a prob if you are not using maya, but the 7xxx series works oK. Im almost convinced that a pro graphics card is very nearly worth it (very nearly almost)
Also if you really want a rush, check out the Boxx site for workstations with 32 cores and quadro cards in SLI ... aaargh
http://www.boxxtech.com/Products/APE...8_overview.asp