A highly configurable graphical desktop and file manager that uses TCL/Tk.
DFM is a file/desktop manager that emulates the OS/2 Presentation Manager.
Filemanager using GTK+, based on Amiga "Directory Opus"
twander is a Filesystem Browser which runs on both Unix-like systems as well as Win32 systems. It embraces the best ideas of both similar GUI-driven programs (Konqueror, Windows Explorer) as well as text-based interfaces (Midnight Commander, List, Sweep). Written in Python ; has a highly configurable UI...
Nautilus - The Gnome 2.0 Graphical Shell and File Manager
It's big, it likes to read everything resembling system configuration, it has a tendancy to crash, and I have seen it "tickle" flaws in SCSI emulation, actually taking systems down...