Best industry animation tool is Sega|Animanium, if your on a budget Hash Animation:Master.
If you have a product like 3D Studio Max, Maya, Softimage or trueSpace the built-in Animation tools are usually the best to work with.
Everything usually depends on what you want to do, and what is within your price range; most importantly HOW serious you are about it.
There is a product TGC have a demo up for (try to download MobileBasic for it), not sure how much it is or if it's out yet, but it is actually surprisingly decent.