Single Player, if well done, can be an epic experience :D

Yeah I tend to play Single Player moreso than online.

When it comes to my 360/Wii sometimes I have difficulty establishing games and finally getting people together without someone getting DCd or the connection kicked or some damn shit.
Castle Crashers has been a royal pain. The one time I played online (finally) nobodies higher levels were near each other so we just played with our lowbies. Then the connection got kicked so I didnt get credit for my last level.

To me it really depends on the game ultimatly. FPS seem tailor made for multiplayer in general and Live (among other things) works well with them.
I played Prey with grahmshu a couple weeks ago and that went well (other than many people no longer play it). MMORPGs to me are the current pinnacle of online gaming. RTSs are also a good genre for it and I'm really really looking forward to HALO Wars!
Other games though can just be a pain. I didn't play much of MKvsDCU but when I play someone who has a different connection speed it screws up the gameplay.

SO yeah there are some games that are SP , or SP and MP and online isn't necissary and thats fine. Other games though Online makes it what it is.

For the most part I still prefer SP because People Suck and often times ruin the expirience for others.

I personally prefer a better Single Player experience over anything else. Having solid online on the side is a must have nowadays though. It's no secret that I am a huge Final Fantasy fan, and FFXI is easily the only game in the series not to instantly click with me. XII set things straight again. I guess this just goes to show that I personally look for a good single player before I look at the online. It's no secret that a game needs both at this point in order to be something extraordinary.

It also somewhat depends on the type of game I am playing. Sports games are always more fun in multiplayer/online. The same applies for some shooters, but not others. For instance, games like MGS4 and Gears of War have amazing single player, but are also complemented by the online aspect. The single player side of them is still what makes them what they are to me.

I dont really have time to play online, plus i usually suck at shooters/ racing games. I like RPG's mainly therefore Single PLayer for me, its all about the story.

Single Player imo.

Are we including online co-op with "online"?

^ I would assume so.

It's worth asking. "SP" might refer to the campaign, and online to the deathmatch. My brother and I play Gears' campaign together online, so I need to be sure.

Single Player- Co-Op- Multi with friends only

i enjoy multiplayer with my friends and its fun to play the military type games with people you can count on not back stabbing you are causing a big ruckus over something that's really nothing, but some of the best games of all time was do to the single player part and a good story to go with them.
I'm afraid some games have lost sight on this and its sad in a way.

Online.