Transmit is an FTP client similar to Fetch, but with many added features. For one thing it also supports WebDAV which means you can use it for your .mac account or any other WebDAV account, very handy. I've tested using Transmit and using the Finder for WebDAV services and Transmit is literally twice as fast and much less prone to interruptions. And the interface is very cool, very Mac-like. Extremely easy to connect and to save favorites, and to transfer file it's Drag and Drop, couldn't be simpler.
I had been looking for an app to sync some of my folders between my hard drive and my external drive when I realized Transmit does syncing but is there a way to connect the FTP side to my external? I sent an email to Panic about it and within 2 days they sent back a solution, it's actually very simple, I was quite please.
Panic also does CandyBar so it is clearly a good company.