1) Fluid. The ability to launch work GMail in one window, personal GMail in another window, and Lala.com in a third window and have them all running in separate

1) Fluid. The ability to launch work GMail in one window, personal GMail in another window, and Lala.com in a third window and have them all running in separate processes that can't bring each other down has been a great help. 2) Eclipse. It's an 800lb gorilla but I've been using it for years (shortly after it was open-sourced). It can do Java, Scala, PHP, and many others. 3) TextMate. Because firing up Eclipse to write a Python or Ruby script is overkill. I also like that I can type "mate ." in the terminal and get the current directory in the project drawer. 4) Safari/Webkit. I used Firefox for a long time, but on the Mac it just can't compare to Webkit, especially once the Developer tools were introduced. 5) Terminal.app. I currently have 3 windows open for a total of 12 tabs. What I really mean is the unix under-pinnings, but Terminal.app is how you get to those. Nothing very exciting in the list above, but those are the apps that I spend 90% of my time using.