Protofile is an awesome FTP client application with tons of features. It supports drag and drop, recursive uploads/downloads, an online ASCII editor and an image viewer and a color-coded status window.

Each transfer is put in a queue and handled in the background, so you can continue your normal operations.

All these features are in a fully customizable, extensible GUI with bars to move all parts. Your sites are kept in a reliable profile manager, so they can be accessed faster.