Cyberduck

If there is a third-party application that stands out for its level of integration with Mac systems, that app is Cyberduck, a FTP and SFTP client capable of working with Spotlight, Bonjour, Keychain, AppleScript, and iDisk.

One of the most interesting parts of Cyberduck is the possibility to access a list of files in a server without having to be connected to it. This navigation is carried out by a file cache stored by the program.

Among other things, Cyberduck helps you recursively transfer directories, resume interrupted uploads and downloads (as long as the server supports it), filter files using a regular expression, and limit the number of concurrent transfers.

Cyberduck doesn't integrate just with the aforementioned systems, but also with text editors like skEdit, SubEthaEdit, BBEdit, Smultron, JeditX, CSSEdit, and PageSpinner.