Setting a User's Default Login Shell
When I became a Mac "switcher" in 1996, it took me a while to get accustomed to the GUI. My mind kept searching for the CLI "under the hood", so to speak. Gradually I came to understand the new paradigm, but now with OS X we've come full circle.
So, of couse, "Terminal" is one of my favorite apps. It's not ideal for everything, but better for some things. For example, I can often ssh to a machine on which the Finder is unresponsive, poke around, and usually fix it or at least reboot it cleanly.