Brett,
there are many more qualified people on the forum to answer this question than me, but here's my shot. If i'm not right we'll both learn a thing or two...
In you're example: AA you're holding the best hand in holdem. Get as much money in the pot as you can, you stand to win a good % of the time with this hand. I'm not folding unless the flop is well coordinated and there is a lot of action to me.
If you need to muck the hand for any reason it will usually only cost you 3-4 small bets (raise preflop 2 small bets, a bet or raise on the flop 1-2 small bets) and when you do take a nice multiway pot with the hand you'll more than make this back.
with KK i'll probably play almost the same as AA although an A on the flop or turn would worry me in a loose passive game.
QQ and JJ, still both premium hands but a lot easier to get away from. In a 5 or 6 way pot, i would be looking to hit my set on the turn if there were more than a couple of callers to a flop bet or raise, otherwise i would be slamming the brakes on.
I hope this isn't too far off the mark, i like to play my premium hands hard and fast as they don't come along too often, and some of the more experienced guys can amend it or add to it.
Good luck.