That gives me an idea actually: what if this time everyone did a mix of what best reflects your own personal music tastes? Not necessarily your favorite songs, but what you find you listen to the most? Or if your actual tastes are too embarassing, you could always throw on stuff you think you should be listening to more.
Basically, if you were to make a definitive mix CD to yourself, what would be on it? I'll bet that would be make for a really diverse group of CD's.
That sounds like a good idea, but I'd rather not restrict anyone. Let your spirit/heart/music collection/sense of humor/need to impress/mood guide you. That's how you end up with the best mixes. Everyone has their own idea of what they want to do or express, and I'd rather not shoehorn those feelings into one tidy concept - especially since we're dealing with 10 different people.
I'm looking forward to hearing new bands, new songs, new sounds - and the simple beauty of a well-crafted mix tape (x9).