I like about 70% of flops seen and a 6 player ring game. That tells me that players are fairly loose, but not maniacal. I also like a middle/high pot size - if it looks too small, the game isn't juicy. Too big looks like there might be serious bullying going on by big stacks (especially if combined with low % of flops seen).

In short, a game where I feel OK about my premium hodling up, but where I can see flops pretty cheap on a prop hand.

A lot of hands per hour is good for bonus whoring. And, if everyone is in for bonuses, they might play too tight, making them vulnerable to real aggressive play. Outside of the bonus situation, too many hands smells like a lot of experience.