I play multiplayer all the time, mostly FPS, but I can play just about any genre and have average skill before too long. Single player is fun too, mostly on games that are focused on the single player such as Half-Life or the many Nintendo games. Even if multiplayer isn't so great on a game, I'll probably be eager to play multiplayer with a friend (or anyone with a DS since it's so uncommon to find DS owners around here). I'm also a big fan of co-op multiplayer, which is great on games where you'd otherwise get owned by the other players, I mostly play co-op in Raven Shield and I'll probably be playing it a lot on Half-Life 2 when the SvenCo-op mod is released for it.
I've been playing multiplayer games since 1999 when I joined the
MSN Gaming Zone in order to play Flight Simulator 98 with other people (that's when I got my name), my love for multiplayer has expanded tremendously since.