Transmit is the best ftp client I’ve ever used. How’s that for a shill? If you’re looking for something a little more indepth, Paul’s review of the current release goes into more detail. For me, the best feature is the tight integration with text editors (I’m partial to TextWrangler). Overall, it’s simple and easy to use, almost feels like an Apple product.
Now comes the hard part where I tell you that Transmit has been my client of choice for two or three years and I’ve only just purchased it recently. Why? I’m a bastard, that’s why — one of those jerks that stiffs the little guys. It’s equal opportunity jackassery though, I steal from the big boys too. It’s mine now though, and worth every penny.