1. Firefox w/Firebug I hate Firefox as a browser on the Mac, but as a professional front-end developer it's the most valuable piece of kit I have. 2. OmniFocu

1. Firefox w/Firebug I hate Firefox as a browser on the Mac, but as a professional front-end developer it's the most valuable piece of kit I have. 2. OmniFocus It's pretty expensive but it's also really really good, and has industrial strength data integrity. Allows me to stay on top of everything at all times. The apparent high cost disappears when you realise that I use it all the time and am able to rely on it 100%. In fact it's my only app with "Start at login". 3. VMWare Fusion Allows me run all kinds of virtualised environments (particularly copies of live environments, and Erlang development environments) as though they're local folders, which means I can use the OS X desktop toolchain to work on code, but use Linux for package management etc. Also for Windows, obviously. 4. DropBox One of the best services on the Internet, bar none. I haven't listed a text editor here as I use TextMate, but am not so attached to it that I couldn't replace it with something else.