I run Mac OS X 10.5 (Leopard), but most of the applications should work on Tiger (10.4) as well.
- Freemind (http://freemind.sourceforge.net/)
- Indispensable mind-mapping application written in Java. I have been using Freemind for years on Linux, Windows and of course now on the Mac as well. Truly useful with some real advanced functions and scripting capabilities.
- An Open Source RSS feed reader. Vienna is a part of my daily routine in which I track a couple of hundred feeds. Once you get to know it you will love it even more - some clever keyboard shortcuts really create a lot of efficiency.
- Firefox is the standard web browser for millions of Windows, Linux and Mac users out there. I prefer Firefox as opposed to Camino on the Mac as I really depend on some plug-ins for my daily security and privacy needs (I'll blog more about this again soon).
- Due to its massive multi-protocol nature (supports over 10 different IM providers) Adium was a no-brainer when it came to Instant Messaging on the Mac. I have never tried iChat or any alternatives mostly as Adium did such a stellar job out of the box. Growl integration makes it even more powerful - I like the ability to do specific actions when certain contacts come online. It also offers the ability to "bundle" accounts from multiple networks into one account for those contact who like myself are on various networks.
- The gents behind Adium also recommend Colloquy for IRC (internet relay chat). My usage of IRC varies depending on project and job focus but I have started to learn the nuances of the program and have grown to love it. I'm not crazy about its default behavior but after a little bit of tweaking it really turned out to be a powerful tool.
- What can one say about Quicksilver? It has changed the way I interact with my computer and probably would be one of the functions I cant live without. The ability to "act without doing" as the developers call it creates the most amazing productivity gains. I am not a Quicksilver ninja yet but the limited ways that I use it in has made life so much easier... Thinking of an app? Three keystrokes and you're there.