Panic are giving away Transmit 1.7 for OS 9, to celebrate the tenth anniversary of the app. I'm pretty sure Transmit (née Transit) is the only app I've used for ten years. Though nowadays it only gets launched very occasionally, thanks to ExpanDrive, which suits my light use of SFTP much better.

It's the 'boring' stuff like this that I'm most looking forward to in Leopard.

Dual pane file manager and FTP/SFTP client for Mac OS X. Great with Bluetooth devices.

From beta testing it (lazily, I must admit), I can safely say that the DockSend and Auto-Permissions features, plus brilliant WebDAV support make it worth the upgrade money.