I hate my mouse. Really, I do. I try to do as much as possible from the keyboard, both in and out of WoW. I have key bindings for just about everything, either in WoW's key bindings interface or using Bongo Bars. If I'm not going to have a key bound to a button, I don't usually bother making it, because I know I'm not going to mouse all the way over to click it. It's much easier to just type "/cast mind blast" than it is to figure out which is the mind blast button, move my hand to my mouse, position the cursor over the button, and click.
But that's just me -- I know a lot of people who play very well clicking all of their spells. I can't imagine it, but apparently it goes on anyway. However, clickers, you are not the subject of this breakfast topic. My question for you today: what are your favorite key bindings? What are the first hotkeys you set up when you first roll on a new realm -- or do you just go with the defaults? My first hotkeys are always "\" for run-lock (because my laptop keyboard doesn't have an easy num lock) and "B" for whatever bag mod I'm using, or for open all bags if I'm not using one.
[thanks, Dr. Funbags, for this suggestion, even if I'm pretty sure you just sent it in to see if I would really write "thanks, Dr. Funbags"]