I want a GUI-ish (and not command-line only) FTP client for Ubuntu. Any good you can recommed?
Gnome has a built-in FTP client, I think it's called "Connect to server". It will open a nautilus window that you can use exactly like a normal one.
Fireftp add-on for Firefox.
Edit Screenshot removed as, although from the fireftp web site and functionally similar, it was not taken on an Ubuntu system and so objected to by some.
Apparently Fireftp it is not yet available for Firefox 3.5 so if you have moved your Ubuntu system to that version of Firefox it won't work (as of today).
Secure: SSL/TLS/SFTP support
Synchronization: Keep directories in sync while navigating
Directory Comparison: Compare directory and subdirectory content
International: Available in over 20 languages
Character Set Support: UTF8 and just about any other character encoding supported
Automatic reconnect and resuming of transfers
Integrity Checks of transfers (XMD5, XSHA1)
File Hashing: Generate hashes of files (MD5, various SHA's)
Drag & Drop
File Compression: Using MODE Z
Advanced properties (CHMOD, recursive CHMOD, thumbnails)