To make MC and Gnumeric better? Or to use an environment that runs well on Linux to run Pinta, Banshee and MonoDevelop which some users (like myself) are using.
Say to me other OSS superstars in desktop area? I know that are many, but I can think just one other name out of my mind (with no disrespect to others): Aaron Seigo, the Nokia corporation backed guy. I like Matz as a great Ruby guy, but there is no GUI person I'm aware to be as popular and passionate about IT.