Or support the awesome guys at Panic and get Transmit. Yes I know I'm like the fifth guy to say this. But it really is awesome! http://www.panic.com/transmit
i usually just use the command line ftp but every once in a while i use cyberduck. the website seems to be down now for some reason but it's a good ftp client.
Transmit's actually the best FTP client I've used on any platform. Great interface, no problems. It's one of the few apps I actually paid for while a college student
In case anybody doing a forum search finds this thread and has the same question, here is a short review by Macworld of Captain FTP 4.2, Transmit 3.2, and Fetch 5.0.1.