What I want is a Pokémon style game.
Maybe I'm alone in this but for me Pokémon is a perfect portable game, you can pick it up for a few short minutes or you can play it for hours. The collectable element is addictive and the level grinding is rewarding (through evolutions etc). There have been numerous Pokémon clones over the years, I rather wish one would get made for the iPhone. Who's with me?