What would be a good mesh designer for Windows?

I am using Unity as an intro to game designing, but I need a simple, free mesh designer so I can create my own meshes. Any ideas?

Blender 3D the best!!!

As @PTerto said, Blender is good, but it is in no way the best. There are many other programs that are better, such as Cinema 4D, 3DS Max, and Maya 3D. Now, if you want something free, use Blender, but if you want something that is the best, those are your top choices.

http://www.sketchup.com/ is by far the easiest for getting something put together quickly.

Blender is the best option for something quality though.