My main interest is for use by the DM: Maps, room keys, monster look-ups, etc. Also, searchable rule books would be a big benefit, as I’m one who uses the book at lot during play. Others claim they rarely reference the rules during a session, so that might not matter to them so much.
But an iPad would also make grabbing images to show the players quick and easy. You could have them loaded and ready ahead of time of course, like printed handouts. But you’d also have the option of quickly Googling something up on the spur of the moment and holding the thing up for the players to see.
Another thing I’ve seen discussed and I’ve thought about is the ability to text private messages to players (“Your PC has been charmed…Play along with the NPC”) rather than written notes. Since so many people have phones with text capability, this would be quick and easy. It would also allow players to communicate privately without other players (or the DM) overhearing. But it would also easily lead to non-game texts, checking football scores, and/or Netflix during sessions, which I think everyone except the guy watching the movie would agree is a bad thing.
So how many players use tables or e-readers? What sort of things do you use them for? And what kind of rules of etiquette do you have?