In my opinion, Filezilla is the best FTP client.

Unfortunately Filezilla is not available on Linux. To use it under linux we use the windows emulator WINE and the windows version of Filezilla.

- Install Wine
yum install wine #under debian for example
apt-get install wine #under ubuntu / kubuntu for example

- download filezilla on http://sourceforge.net/project/showfiles.php?group_id=21558

- install Filezilla
wine FileZilla_2_2_32_setup.exe

- execute Filezilla (create a shortcut to it on the desktop for example)
wine /home/matt/.wine/drive_c/Program\ Files/FileZilla/FileZilla.exe