How to: cut an onion

I'm making chicken fajitas tonight and I just finished prepping everything - marinated some chicken, sliced up some peppers and onions - for cooking off later. Every time I work with onions, I get a little thrill when I chop them (how's that for being a cooking dork?) because it's one of the few cooking techniques that I've mastered. I actually don't remember where I learned the proper way to do it (maybe it was either in high school home ec or from the Food Network?) but it's a great skill to have because onions are everywhere.

So how do you cut an onion properly? I'm going to let Gordon Ramsey give you the full lesson, because he's much more bad ass than I am, and everything sounds better with a British accent anyway. My bit of advice to you would be this: get a good knife. We have this set of Wustof Classic knives and it makes such a difference when you're slicing and dicing.