also have a look at 3d coat. [www.3dcoat.com](www.3dcoat.com), it could look a little advanced at first, but really its actually very simple, and creates very stylish graphics... great organics and great mechanics.
voxels are kinda new... http://www.youtube.com/watch?v=PwtKI\_Cx6Dw&feature=related so maybe its best to stick to textured polys.
leave the advanced stuff till later.
first things you should make sure you know how to do, is modelling, uv texturing, skeletal animation, collision detection, landscapes (for your environment) game play scripts and ai/bot scripts and networking, then youll pretty much have it all covered.