My top 10
- Ubuntu Linux (and all the goodnees that comes with it):
http://www.ubuntu.com/
as far as individual programs
- Scribus (DTP goodness): http://www.scribus.net/
- Inkscape (Illustrator like goodness):
http://www.inkscape.org/
- Quanta Plus (I'm a web programmer): http://quanta.kdewebdev.org/
- SuperDuper (Macintosh clone/backup, excellent):
http://www.shirt-pocket.com/SuperDuper/SuperDuperDescription.html
- OpenOffice.org (the draw portion is way underrated): http://www.openoffice.org/
- Linux/Apache/MySQL/Apache (the LAMP stack as it is referred) a DB programmers dream team for making web apps:
http://en.wikipedia.org/wiki/LAMP_(software_bundle)
- FamFamFam silk icons - hundreds of 16x16 pixel icons that all work together for web pages:
http://www.famfamfam.com/lab/icons/silk/
- A graphical diff compare for files and/or complete directories!: http://meld.sourceforge.net/
- KFileReplace (part of Quanta), global text search/replacement to a file and/or directory tree (if you are a programmer you will know.): http://kfilereplace.sourceforge.net/
The nice thing about FLOSS is it's at its core are a lot of developers helping make life better for themselves and other developers.