You lucky person, you've landed when I actually have something useful to say! Or rather, Tantek has something useful to say; my useful thing to say is just a link there. :)
On the Proper Use of the Class Attribute--or "A Touch of Class", which is the real title (and also happens to be the name of a template project I'm (supposed to be) working on).
What? Oh, right. Here's the Table of Contents.