I personally always looks for the deepest stacks in games I play online or in a casino. You make the most money from other people making mistakes, like not protecting a hand or not raising with big pairs. These mistakes usually mean that the player overcompensates and overbets the next round. In a shallow game, they dont have much left to make them pay, the deeper the stacks the more you can make the pay for mistakes.
The things I look for in a game. I like a game with one of two LAg players. These are the players I look to trap when I make a hand. I also do very well vs rocks and having a couple of those at a table is good too. I can usualy push them around and if they push back its time to fold. With a couple of these at the table it makes it possible to avoid the good tight agressive players unless you have a big hand.