One of the great things about the Mac is the pervasive keyboard support. When I first started with the Mac, I was kind of annoyed that it doesn't have as much consistency between applications for keyboard shortcuts, and the ALT-key combination style from Windows isn't as well supported (most applications primarily do APPLE-key combinations).
Then I discovered two key keyboard shortcuts: CTRL-F2 and CTRL-F8. CTRL-F2 sends focus to the menu, highlighting the Apple logo on the upper left-hand side. Then, you can start typing the name of the menu you want to invoke. When you hit the one you want, hit RETURN and it opens the menu, ready for more incremental search typing. This I find is even faster than the ALT-key style combinations in Windows because it is consistent across all applications (well, except for abysmally bad applications like Lotus Notes), and you can type the first part of the menu item you want very quickly. Incremental search is a powerful way to get to stuff in a very few number of keystrokes.
CTRL-F8 focuses the task-tray portion of the menu bar, allowing you to highlight some of the icons (like the AirPort icon) and turn on AirPort from the keyboard. CTRL-F8 + some arrow keys gets you into the icons that allow keyboard access.
I recently found another great use for this. I use an EVDO card for ubiquitous Internet, and I've been starting the Verizon Wireless little application to start the Internet connection. I was talking to Jason Hunter this weekend, and he just turns on the modem display (found in the standard Apple utility Internet Connect, you check the "Show modem status in menubar"). This allows me to CTRL-F8 up to the menubar, pull down the list, and get online with EVDO faster.