Thanks for all the kind words. I appreciate it!
As for the couple questions about which 3D program I use. Actually very few of the matte paintings I've done used 3D. The exceptions were the LXG fortress/factory which was Cinema 4D. We got the rough models from Escape and then I added the texture maps in Cinema 4D. All the finer details (small roof windows and tiny spires along the edges) were added later in Photoshop.
I was also given rough models for a couple of the foreground buildings in the Riddick mattes. The came rendered with flat grey lighting and I painted on top and added detail.
I'm starting to use Maya since the guys I most often work with use it so it's easier compatibility wise but I did really like Cinema 4D and had used it in my motion graphics quite a bit.