I've played with Animation Master; it outputs to an avi file or mov, or even a sequence of tga's. Seemed to be pretty powerful (for the limited stuff I did), but as I've not used anything else I can't really compare. The price didn't seem unreasonable.
I use 3ds max version 6. Terribly expensive but the only other programs even close to it are Lightwave and Maya. Super-powerful, but not forthe faint of heart.
Poser. It has a pretty steep learning curve but the results can be amazing once you master the basics. Ideal if you don't have any "drawing" ability yourself, since it comes with a whole host of models, easy to customize, there is a large web community, and the figures can be posed very realistically. Typical export to AVI, Flash. Easy movement in X,Y, Z space, multiple camera angles, lighting, the ususal goodies. Plus rather inexpensive. I just upgraded to version 5.
An animated "BillyBoy" coming to my new web site... soon.