The multi-protocol instant messaging client for the Mac. Handy if you have MSN, ICQ, and Google Talk accounts (like me).
The only adblocker for Safari that isn't implemented as a hack -- this one is actually a proxy that filters out the stuff you don't want to see.
Simply the best torrent client for OS X.
- Google Notifier + Google + Growl
A menu bar app that notifies you when there's new mail in you Gmail inbox. The Google + Growl utility makes sure the notifications are Growl compliant.
A notification system for Mac OS X. Many programs are capable of using it, and it's a functionality that's lacking by default in OS X.
- USB Overdrive
The default mouse acceleration is really crappy on OS X. USB Overdrive lets you change it according to your own tastes.
CDto adds a button to Finder that opens a Terminal window and changes its active directory to the Finder directory.
Plex is a home theatre app that is much more versatile than Front Row. Amongst other things, it can pull content directly from the internet to your TV.
Perian adds playback support to QuickTime for a whole range of media format.
Adds WMV support to QuickTime.
If you've got a Last.FM account, this little app is for you. It scrobbles all your plays in iTunes.