A couple years ago I realized that if I had a good terminal environment, all I really needed was a terminal, browser, and IDE.

So, by using Linux, I lose, I dunno, iPhoto and iCal and whatever, but I gain real Linux with a real Linux package manager and immediate access to the latest version of every tool I can imagine. Plus fun stuff like BTRFS, a tiling window manager, and a feeling that I'm actually in control of the system I spend 8 hours a day in front of.