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.

This is my fave feature of Transmit 3.0 - all the portions of the site I tinker with a lot have their own little combo of Transmit Favourite and mirrored local directory now, so updating is a simple as a couple of Quicksilver keystrokes.

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.