OpenSourceMac.org clearly presents most of the best open source software projects for Macintosh. Some of my favorites are here, such as Camino and Celestia. I also learned about some new applications that I will have to try, such as Cyberduck (FTP client) and Vienna (RSS reader). While shareware stalwarts NetNewsWire and Fetch work well for me, free works better, especially when others ask for recommendations.
Referred by: Tim Wilson