Awesome
Voxelator
Voxel stuff entirely on the GPU using lots of GPU stuff and very little CPU stuff. Requires GLFW, GLEW, OpenGL, and a computer with a fairly recent GPU.
Has SSAO, cheap greedy meshing, light sources. Maps are loaded from Miecraft map files.
This is mostly research code, so it's not typically clean. It was written and tested on an NVIDIA GTX 770, so YMMV on AMD hardware.