PK,
Against 3 other random hands, AA is only going to win about 25%-30% of the time... that's not a favorite to win. It IS a favorite to win vs any other single hand, but that's of no concern to you because you have to overcome all of the other callers. Somewhere around 60% of the time you will lose with AA vs. 3 other callers... that sucks!
Also I think I would take into account the fact that callers will be calling with hands that are most likely NOT random. PK brought up a good point that they might hold AK or something where you are a HUGE favorite, but lets say 3 other callers all hold a pocket pair (88, TT, QQ). That's 6 outs, not counting the smaller outs of someone making a runner straight or flush, that can beat you. Those AA sure have shrunk up a bit now!
However, I think that this post has gone a little off of what Quads originally posted. With AA here you really need to bet big to isolate... most people won't call a raise and a BIG reraise, especially on the first hand. The original raiser raised 5X the BB ($250), so a raise to $1000-$2000 would be enough to see where you stand, who folds, and who (if anyone) decided to go all in. Gotta make that all-in call if 1 player goes all in and either no one else or 1 other player calls. 2 callers, I'd still probably call, putting them on AK or KK and hoping to triple up and ride out the first day easy!!
On one more side note (sorry about the long post), there's also a chance that anyone who would go all-in on the first hand of a HUGE tourney might also have AA himself! Slim chances, I know, but if a logical player is willing to push on the first hand, I really have to put him only on 3 hands (AKs, AA, KK) unless he's aggressive or just plain stupid!! Well, that's that. I think I'll have bigger problems in my tourney career than whether or not to make a decision on having AA on the button on the first hand lol!!
-David "kid"