Open source software

Ever since I found out about Synergy (a free, open-source piece of software that works just as well as the $70 one I bought) I've been researching other open-source software. There is some good stuff out there. Some of the best is located on the TheOpenCD.org. There is a free sound editor (very similar to CoolEdit), a free PDF maker (like Acrobat), a free HTML editor (similar to DreamWeaver), free zip/unzip software (like WinZip), and much more. I've just played with them a bit, but so far I'm impressed.