gFTP
gFTP is a free/open-source multithreaded File Transfer Protocol client program. It is most used on Unix-like systems, such as Linux, Mac OS X and Sony PlayStation 3. It includes both a graphical user interface (GUI), which utilizes the GTK+ graphical toolkit, and a command-line interface.
Supports bookmarks
GNOME Commander
This just crashes when attempted to add an FTP site to connect to.