There's an in-depth post on The Denver Egotist on this subject at the moment, Part 1 here, Part 2 here.
It's worth reading, though as I say, it is long. And I have a short attention span. So I thought I'd throw the question over to you guys with a challenge to put it more concisely.
What would you say makes a good CD - or a bad one - using as few words as you can.
Here's my entry. A good CD "says no nearly all the time" (6 words).
Oh, I've got one for 'bad CD' as well. A bad CD "is woolly" (2 words).