So I'll start this off with an awesome collab. comission that I just got.
I did the pencils and inks (here's the original- http://toddoss.deviantart.com/gallery/#/d30995p ) but wanted a pro colorist on this so I comissioned Mark Roberts http://markhroberts.deviantart.com/ to color this for me so I can sell prints at conventions.
It blew my mind how good of a job he did. It makes me feel like I'm a good artist or something when he makes it look a 1000x's better with his colors. He was super fast and very reasonably priced.