I hardly ever play multiplayer. I dont see the point its just doing the same thing over and over. I buy a game play thew single player for the experience then sell it.

Single player only pretty much. The only online gaming I ever do is in GT5 and in games where it is a part of the campaign (Dark Souls, Journey)
Local co-op is preferred, but as a father of 2 and my friends having kids too, that never happens anymore.
Although co-op with my 3 year old in the unfinished swan was fun. Him messing around with the move, me with the navigation controller trying to somehow get somewhere :)

mp definitely, i really like the competitive experience of playing mp with others online or splitscreen

Campaign. I only care for online in MMORPGs.

I am almost exclusively a single player gamer. When I do venture online it's with real life friends/family in mostly co-op stuff. The most time I've spent online with people I don't know was in the very fun team co-op Mass Effect 3 multiplayer mode.

Heroes of Newerth is the only online game I play... But I play it 95% of my free time. I also hunt for trophies on my ps3 in single player games, in between HoN matches.

I have my consoles where I can play with my friends, and online isn't available there. So my answer has to be campaign I guess.

It depends on the game. I tend to focus on the campaign for most games, although certain games are built for online (LittleBigPlanet), and I mostly play online in these cases.

Co-op campaign > LAN > campaign > splitscreen > online multiplayer


As for playtime, I probably end up playing more online multiplayer than anything else though.

Single player.
Except for some mmorpg sessions in the past.