Having recently bought myself two wide screen monitors purely for development purposes, i began thinking about potential design choices for games which could leverage the users' extra monitors.
I am not aware of any games that use multiple monitors in an interesting gameplay-wise way, similar to what the new consoles are offering with their "LCD screen on your controller" scheme, and having a minimap always shown on the other display (i remember seeing that somewhere).
Note that this shouldn't apply to multiplayer games because you want to have maximum fairness in those, where neither player has an obvious advantage just because they have more money to throw at peripherals, but rather single player games.
The choice also has to be optional because not everyone has more than one monitor, and the game still needs to be playable on a single monitor computer.
If you had the money/freedom/need to design an optional feature for multiscreen setups, what would it/they be? Minimap on the second screen? List of party members? Inventory always shown?
I'm interested to see what different people would do if they had the option.