If he's bad, I can see it being AQ as well I suppose, or JJ, but he'd have to be pretty bad to call preflop with AQ and to minraise on the flop with either of those hands.

As for AA...I can see a good player lay that down in Helmuthian style. Think about it, if you have AA and you raise preflop, and then you are reraised...you figure villain (who is tight) has AKs, KK, or QQ for the MOST part. Flop comes KQx...so now all he is beating is AK. Is Ak going to play back at him that hard, knowing that villain could have AA? Maybe not...just a possibility heh