I'm in the process of building an arcade controller for Launchbox/MAME/etc. I plan to add buttons for exit, pause, start, coin, select and favourites. May as well have them if you're building it yourself! Wasn't going to bother with volume as it's not a cab, but I would want to have some kind of volume control in a cab. I know some folks use button combinations to access these functions, but I'd rather have it plain and simple!