A free version of "Photoshop."
Vi (improved). This or a some nice text editor
is a must for anyone who programs. Syntax highlighting, keyboard
commands, etc…
www.vim.org
This a free cad package that is light.
http://www.cadstd.com/lite.html
Useful
Web Applications
If you are not already committed to a
calendar system this is nice. Even if you are you can import your
MS outlook or iCal calendar very easily.
(Sharing with a community, access to public
calendars, and you have it anywhere)