I'll push
Blender as always. I found it very powerful - plugins, scripting, ability to use external renderer, subsurfacing, boolean operations, some NURBS capabilities, a lot of
tutorials and
creative community. And native export to .X (in 2.36 at least). And free.
The only problem is interface. It's not a newbie friendly. But people who got accustomed with it told it's very comfortable to use.
edit: fixed links