Krusader is a twin-panel (commander style) filemanager for KDE. It supports mime-type, complete drag n' drop, multiple filesystems, archives, bookmarks etc. Krusader's GUI is intuitive, and allows an easy access to all of your file-management needs.
A dosbox frontend written in PyKDE. Rather than concentrating on dosbox configuration management over multiple games, this frontend concentrates on file management.
Familiar is cross-platform Family Tree management (Genealogy) Software using QT. It supports viewing/editing file tree using drag-drop in multiple ways. Events allow you to define events in any number.
KBear is a graphical ftp client with ability to connect to multiple hosts simultanously. You can copy/move files or directories between the hosts by drag'n drop or cut'n paste. It also has a dynamic site database.