MacFusion is a graphical user interface for MacFUSE. In a nutshell, it lets me mount remote file systems with a mouse click. The FTP protocol is supported as well (finally read/write FTP on MacOS X via the Finder!), but who wants that if SSHFS is an option?
Update 2008-01-08: iTunesFS
While we are at it, iTunesFS is worth looking at, too.