FileZilla is not only one of the best-known FTP-clients but very famous program too. Having a wide range of functions it is absolutely free. It is one of the most successful OpenSource applications.
The second version of FileZilla was developed and modernized for a long time. But the third one took its place. There are a lot of interface modifications and new features in the latest version. In addition a version for Mac OS X was released.
The other day FileZilla 3.5.1 was released. Modifications for this version are in bugs fixing. It is possible to download FileZilla 3.5.1 on the official page of the project: