I just went to a demo put on by Alias last night. Man 6 looks killer!
The Mental Ray renderer supports Hair and Fur and everything now so you can GI and FG all that stuff.
Also one of my favorite parts was the Geometry Mirroring. Our demo guy made an entire Ifel Tower out of a simple 3 sided curve and then duplicated and mirrored it with the new feature. It was awesome.
Also the fact that deformation lattices now have fall off so that your objects (be them geometry or particles) don't freak out when the leave the lattice, but rather they just continue to either decrease or increase in magnitude. Really way cool.
Also the Photoshop integration is tight! Really nice stuff you can do with that.
Let's see what else.... oh yea, Paint Effects now supported on Polys and the animation parameters of Paint Effects is enhanced.
Just too much cool stuff! I think I need to lie down.
"Please excuse the crudity of this model, I didnít have time to build it to scale or to paint it"
:: Dr. Emmett Brown