Apps for anything and everything. One I use is coconutBattery, an application for those of you with a MacBook or MacBook Pro. It tells you the percentage of the battery charge remaining and how healthy your battery is (how much of its original charge it can still hold). You can find it here:

http://www.coconut-flavour.com/coconutbattery/

What free apps do you use?

I use a similar app for my battery info however it is in the widgets (iStat Pro)

I am sure there is already a similar thread to this further down or on the next page.

flip4mac is good for playing windows media files through quicktime:
http://www.flip4mac.com/download.htm

applejack is a good diagnostic assistant:
http://applejack.sourceforge.net/

http://chmox.sourceforge.net/ - Read CHM help files.
http://www.9031.com/downloads/screensavers.html - Cool screensavers.
http://www.derailer.org/paparazzi/ - Take screenshots of whole webpages.
http://cyberduck.ch/ - FTP.
http://www.freemacsoft.net/LiteIcon/index.html - Change icons.
http://handbrake.fr/ - Rip DVDs.
http://perian.org/ - Quicktime support for additional video formats.
http://paintbrush.sourceforge.net/ - Like MSPaint.
http://www.transmissionbt.com/ - Torrent client.
http://code.google.com/p/formulatepro/ - Write on PDFs.
http://simonhaertel.de/quinn - Very addictive tetris.
http://safariadblock.sourceforge.net/ - Adblock for safari (no 10.4 support).
http://cabos.sourceforge.jp/ - Lightweight gnutella client. Better than frostwire.
http://www.adiumx.com/ - n/a.
http://limechat.sourceforge.net/ - IRC client.
http://www.unrarx.com/ - RAR and other archive files.
http://darwingimp.sourceforge.net/ - GIMP for mac. Needs X11.
http://www.videolan.org/vlc/ - n/a.

I forgot about iStat, I use that one too. Sorry if there's a similar thread, I didn't check first.

thepiratebay.org has quite a lot of good, free software.

It does.... But I was thinking more alone the lines of legal free software.

I doubt a lot of this is free software, regardless of how much it costs.

I've got OSX running in a VM I set up on windows. At the moment I've got Logic, Pro Tools, Melodyne, and a few other things. Sadly I can't get firewire working in VMs yet.

But yeah, all free

Smultron is a great freeware text editor.