On the Things I Wasn't Expecting list: my new laptop doesn't have VGA output. And my existing monitor only has VGA input. I'd been hoping to plug the laptop into my existing peripherals for everyday at-home use (Q: Why? A: Ergonomics and because I tend to eat and drink at the computer.) so this threw a wrench in my plan.
The solution: a VGA to Mini DisplayPort adapter. The Mini DisplayPort (with which I was unfamiliar going in) is another video input, and is located (as of December 2010) at the back right (as you're facing the screen) corner of the computer, just behind the XPS logo. I found them at Future Shop but not The Source, but didn't look anywhere else. Apple appears to manufacture them, so you can probably get them through the Apple Store too.