I'd disagree.
Working backwards, I liked Black Ops' campaign and multiplayer. The story was something different and the online's... I dunno, fun.
I liked Modern Warfare 2's online too. Yes, it was horrifically unbalanced and generally broken, but that meant I was so astoundingly bad it was one of the few games nowadays I don't care if I win or lose, I just enjoy the ride. From behind my riot shield.
Don't particularly remember the campaign since I originally rented it before buying it so rushed through it for the achievements.
Modern Warfare's online seemed kinda dull to me. Yeah, it was balanced and probably overall better, but I just never enjoyed myself as much.
Campaign has the same problem as Modern Warfare 2's. I achievement-whore'd it.
I should really play those campaigns again...