One thing that makes me a better developer is keyboard shortcuts, the problem is that they aren't very discoverable and you usually have to download a keymap for each application.
After using my Mac for awhile I really missed the alt key from Windows to pull down menus. Jonas introduced me to Keycue for Mac OSX, it is a utility that shows all keyboard shortcuts for the application that you are using after you hold down a hotkey (the Apple key) for a certain amount of time.
Now I am left wondering why Windows doesn't have something like this!