I think I've lost more money raising with AA than limping in with AA. Sometimes I might be in good position, have a couple callers in already, so I throw out a raise of 4 - 8 times the BB. If one of the blinds calls, that increases the chances someone else calls (hey, big pot, right?!). You get a favorable flop, so you raise again. One of those people had stayed in with suited 7,8 or something and now has 2 pair, a straight draw, flush draw, something, they hang in and take you down... As someone mentioned, being able to lay them down is huge either way...

So I find I just play the big hands differently depending on position, the table, tournament/cash game, etc... Besides, who wants to be predictable anyway!!!