Wow helpful people here so far
Are you looking to build yourself or buy a pre-built setup? IF I had to build a Dual rig right now for Adobe and 3DS, I'd go for:
ASUS K8N-DL (Or nice Tyan board depending on your budget) + two Dual Core Opteron 275s or 280s (Or Dual Single Core Opteron 252's and above)
4GB RAM at least
And Graphics card that all depends. I'm not sure if you are a workstation card user (FireGL or Quadro) or a consumer card user.... But for a workstation, I'd get the best Quadro card I could afford, or either an ATI X1900 Series card or GF 7900 series.
Or if you can stand to wait a couple months, it looks like Intels Woodcrest Xeons could rain on Opterons parade. Regardless, once Woodcrest comes out Prices on Opterons are probably going to drop anyway if you still want to go the AMD route.