Hi, I use an Open Sourced modeller called Wings3D.
It's a truly amazing tool.

So easy to pick up, the basics are simple, yet it is very powerful.

It lets you do all sorts of operations on either vertices, edges or faces.

http://www.wings3d.com/

So yeah, my models tend to be simple and fall under what you would call "programmer art."
So sometimes, if I can't model it myself, I will occasionally buy a model.