When I made some changes to this site recently I used the great little FTP program, Transmit. I was very happy with its useability then and I still am. I particularly liked the little dashboard widget you could set up so you could simply drag your files to the widget, it would load Transmit and send your files all while the truck rolls along.
Of course, FTP isn’t the most secure of protocols and I certainly wouldn’t be eager to open up FTP on the server at work. Fortunately Transmit does Secure FTP (through SSH) right out of the box. And using it is as simple as normal FTP.
So if you have a Mac and use FTP for more than just basic transfers (which the commandline client does superbly, even including tab-completion for remote filenames, something severely lacking from other commandline FTP implementations), get Transmit. It is money well spent.