I want a tabletop wargaming app on the iPad! Games Workshop NEEDS to build a tabletop miniature wargaming engine and then start offering all their games that way. They could make a fortune on in app purchases of virtual figures/army sets, terrain kits, pre-made maps and scenarios...
Local multiplayer online multiplayer, single player campaigns vs AI, online leagues... gah. I would seriously drop so much cash on this.
Also, tabletop RPG gaming system could be cool. iPad for a shared screen of maps, dice, general info, etc, and then tethered iPod/iPhones for each player to have character info, private messaging, etc. and a DM mode for a tethered iPod or iPad as well. Would be a pricey setup ($200 per player, plus a $500 iPad or two) but I could see D&D nerds (said with love!) coughing up the money - it's not like they are single purpose devices or anything.