Anything with the new Xeon E3's (sandy bridge) combined with the C204 chipset would make a fine workstation. I would definitely add an SSD though. Some applications use a scratch file on a hard drive regardless of how much ram you have. The creature comfort of a much more responsive machine is also a nice side effect.

VERIFY application compatibility before purchasing a card. Either the 6950 equivalent firegl or low end fermi quadro are $700-800 and would perform great.