Some Cool Free or Open Source Software

During the last year I have read a number of tips of places where one can legitmately access free or open source software applications, with some restrictions. Obviously, there are tens of thousands of apps and I am familiar with Sourceforge etc. I have been pleasantly surprised at the number of useful little programs that one can access free. Typically, if you want the full features you have to subscribe or pay for a customisation service, which is fair enough. Here are a few sites I think are cool, useful:

Gliffy - great little online flow charting program

Freemind - easy to use mind maps

Basecamphq - Online collaboration/project management

The Gimp - Image Manipulation Program

NVU
- A Front Page style web designer for Linux as well as Windows and Mac desktop users

Thunderbird - email client alternative to Outlook (not quite as good but virus free- so far)

Filezilla - Windows like FTP client

Open Office 2.0 - Fully featured alternative to MS Office

Firefox - Web Browser (of course)

Drupal
- Enterprise quality Content Management System

SugarCRM - Community edition CRM

Anyone got any other nifty little sites they don't mind sharing?