I think you should check out these engines. They are completely free, open sourced and fairly professional:
Java:
jMonkey
Python:
PyGame,
Panda3d,
Game Blender
low level, C++ and others:
Ogre3d,
Crystalspace3D,
Irrlicht3D
I find Blender and jMonkey the most interesting atm. And that's also the big difference. You don't need direct hardware access at all.