Basically, any gameplay thats fun. It doesnt hav to be completely innovative or new or anything. I like a good soundtrack and an interesting but not too involved storyline. And most of all i like options. Like customizables, user created content and lots of choices and well....options.
Graphics are always a bonus, but they dont make the game.
And whether or not it has a multiplayer is their choice but if it does, it should be good. REALLY good. And if not they should hav more time to focus on the gameplay alone.