This was something i was reading in a mag about games you can play online ,basically is nesscery? from my experience of the games that i have got i would definitely say yes the ones that usually it,i think it gives the games a bit more longevity.
take cod4 i have never played a game as much as i have this one if it wasn't for online play i would have played it twice at the most and that would have been it,so i think all games should come with online capability,thats if the developers can do that with each game and have time to obviously.

ive been playing since i was very very young on an amstrad and was fine with single player the games where longer more challenging now i complete most games in the first day of purchase and even the rpg's arn't long enough so until they make quality game that take a while i think online is essential.