A file damager
It has been modelled after the famous Amiga file manager Directory Opus. It has two-pane directory display, command buttons and user-definable directory shortcuts.
It is capable of launching external applications to handle files, and it also has hex and text view mode.
Its GUI is built with GTK+.
Sadly, it doesn't understand mime.types or XDnD drag-and-drool protocol (ie, can't interface with GNOME stuff that easily). =(
Excuse me for using terms like "file damager" and "drag-and-drool"; To be honest, gentoo was good enough for me to make a point that "command line isn't the only way".