This one goes hands down to role playing games. Not that massively multiplayer garbage. Old school, 40+ hour, RPGs. With cloth maps! Hack and slash or story based there are few kinds of RPGs I don’t enjoy. Over recent years there has been a lot of RPG bleed through into other genre. In some cases this is a mechanical effect: loot, experience, levels and in others it is a bit more subtle. Something like Mass Effect 2 is an RPG, but at the same time it’s action heavy gameplay mean it trends towards an action game as well. I used to joke that ability enhancing equipment in Tiger Woods were magic items; was I wrong? Everything from Call of Duty to Halo: Reach have turned to the carrot of experience points (or credits, or whatever) to lead you ever onward.
King of the Nerds!!! 