Very good advice from jbgoode and grumblbrum, you must also consider what types of players there, if they are very aggressive and pay a lot, you better play quietly, also depends on how good your post flop play, if there are tight players, you can take your stack to put pressure.
You must be careful with another big stack, especially if it is a maniac player, you must also take into account how many chips are villains, not just to look out in your stack.