I failed to mention yesterday that Panic Software released Transmit 2.0, their outstanding FTP client. Version 2.0 has been rebuilt from the ground up using the Cocoa APIs, and is Mac OS X-only.
I helped beta-test this release, and it’s been really solid for me. I like how it handles both regular FTP, and SFTP, which is how I connect to my own domains for file transfers. Give it a try, and support future development by registering the software.