My big complaint with multiplayer is that it's all online these days. My husband and I don't generally play the same types of games, but when we do find a game we both enjoy, we're either stuck buying two copies (for PC or DS) or taking turns watching each other play (because I can't justify a second XBox or PS3).
The last game that we've played together, in the same room, on our television, and really, really enjoyed was Little Big Planet. That's pretty sad, when you're looking at two gamers.