Pocket aces (AA) is the best starting hand in Texas Hold 'em, being the highest pair available in the game. This is a hand that should always be raised preflop. Novice players sometimes slow-play AA, thinking that the best strategy is to induce lots of callers with the idea of trapping their opponents. However, this strategy is dangerous, as it opens the player to straight and flush draws, as well as "garbage" two pairs.
The ideal approach with AA is to raise pre-flop, with the intention of building pot equity, clearing the field of drawing hands (i.e, suited and connecting cards) and reducing the opposition to those holding lower pocket pairs or large unpaired cards (e.g., KQ). Of course, this is easy to accomplish in no-limit games. In limit hold 'em, however, the value of AA depreciates somewhat due to the inability of the player to raise enough to drive out inferior yet dangerous hands. For example, a player with AA in the dealer position, facing a field of 6 limpers, will be unlikely to force any of them to fold if he raises, as he can only raise the increment allowed in the game (e.g., $5 in a 5/10 game). In limit games, AA should still be raised preflop to increase the holder's equity, but the holder must realize that previous limpers will likely call, and be cautious of flopped two-pairs, sets, straight and flush draws.
|PokerWiki's guide to limit hold 'em preflop play|