http://blogs.sun.com/roller/page/richb?entry=essential_mac_os_software_tips

http://www.techbabu.com/2009/11/21-awesome-apps-for-mac-os-x/

http://homepage.mac.com/ulyssesric/bestpicks/

http://blog.refactor.se/blog/conlun/mac+os+x/?permalink=OS-X-musthave-software.html

Widget: http://moment.myftp.org/

Python development environment: http://www.postneo.com/2006/04/26/my-osx-development-environment

Comprehensive list of OSS at mac - http://www.macdevcenter.com/lpt/a/6669

Linux / Unix OSS list, probably useful for Mac also - http://blogs.sun.com/richb/resource/freeware-list.html

Macport, probably something cygwin in Mac - http://www.macports.org/

Space saver of mac - http://www.xslimmer.com/

Password saver - http://switchersblog.com/2008/01/30/safari-autofill-for-iphone-and-ipod-touch.html