My personal list of wonderful GNOME-and-related progress in 2004. It's been a good year:
- GTK 2.6 added new API that we really wanted, really quickly. Though lots of people worked really hard on this, I believe that Matthias Clasen has been a major organisational and coding factor. Red Hat was very smart to hire him. 
- Frederico and friends did lots of little-details work on GtkFileChooser, dealing with the wrath of the typing-the-full-path crowd and adding nautilus-style keyboard navigation, to make the experience even more mac-like.
- Fedora finally merged with fedora.us, to create pre-extras, so people can now get extra stuff like gtkmm from a definitive source, and the way is almost clear for a debian-like community to evolve.
- Ubuntu showed how to fix Debian.
- USB memory sticks just work.
- Fluendo got serious about gstreamer.
 Matthias Clasen is still largely a mystery to me. I couldn't say what he looks like, where he lives, or what he cares about outside of GTK . That's probably best though, because I'd fanboy him.