[Jekyll]

it really depends strongly on the game.

if i'm playing a limit game, and everyone's playing so tight they fold to most early position raises, i'm raising every time, aces or not. the only time i start limping is if i find myself with a highly aggressive player on or near the button, so i can re-raise the likely raise.

the same principle can apply in no-limit, but the dynamics are a little different. because of the ability to increase the size of the pot much faster, you can sacrifice the opportunity to re-raise preflop to disguise your hand. BUT, you must have the discipline to fold to an unfavorable flop.