There's a big difference of opinion between two people when it comes to showing hands, and for good reason. One argument against showing your hands is that players can go back and see how you reacted in different situations, and they will see that you're capable of bluffing, slowplaying, etc.

The other side of the argument, the one I believe in, is that the best way to establish an image is to show down certain hands. If you want to be seen as a player who bets with the goods, you show down your hand when everybody folds. People start to believe that when you bet you've got a hand. On the contrary, showing your bluffs will increase your opponent's likelihood of calling you down with a marginal hand, and you might get paid off where you wouldn't have unless you showed down the bluff from earlier. I think it's an interesting topic, I would like to hear everybody's thoughts and opinions on this.