I always play SP first and don't always even try online. I haven't touched online in Bioshock 2 and probably won't - for me the effort to add it was misplaced. GTAIV I've never bothered with online, either.
Perhaps as punishment, the only game recently I did want to go online with, AvP, has proven to be weak so far. I want to play full games of Infestation and there never seems to be enough players to make it come alive.
I got it on PS3 because my eldest son wanted to play there but I think I'm going to have to buy it on PC as well and try that.
I'm more an SP, offline coop kind of player on consoles. My main online gaming is on PC, mainly Valve titles over Steam - L4D 1 & 2, Day of Defeat, Team Fortress 2, etc But even there I haven't been online as much recently.
TBH I've been finding online kind of boring and repetitive of late - the arguments I think many use for it not being repetitive, playing humans, etc. just don't hold for me. I find that on consoles there tends to be too few maps, too few players, too much matchmaking and too much chatter! Also too few mods and custom made maps.
I think I'm falling out of tune finally with gaming trends. Still, I've only been playing games for like 30 years or more so I can't complain!