I've really been enjoying the fruits of the open source world lately.
I've been learning and using OpenOffice a lot more. Even been
converting some old WordPerfect docs into it. I've been recommending it
to people who need a word processor. I've even installed it on a
terminal server for those users to use (I did it because we couldn't
justify MS Office). I've even donated a few dollars to the project.

I also encourage donating to any open source project that takes donation
and you find useful. No reason not to in my opinion.

Along those same lines I've also started using VirtualBox at home for
just testing purposes. I have to admit I kind of like it. I'm not
gonna go and compare it to vmware workstation, but for what I do it's a
suitable solution (and far cheaper).

Some other open source or free applications I like and use.
Aptana Studio
Netbeans and Eclipse
Linux (obvious one)
Firefox and Thunderbird

I admit most of those are trivial at this point. Things like Apache and
firefox are so commonly used that they can go without mention. :P

Anyway. Go Open Source and Free software. Your making my life a little
better everyday.