Hey, I noticed this wasn't on the original thread. It's not mine, it's just something really awesome that someone might not have heard of.
www.blender.org - You'll find a great tool for 3D modeling and animation. It even has a game engine (not
very powerful, but good game can and have been made with it).
Hope this deserved its own thread. If not just move it. Can't believe no-one else thought of this.
(Um, at the time of posting this, the site seems to be having problems. It should work soon, though)