To be honest, I've put in thousands and thousands of hours into Halo 2, 3, Wars, ODST, and Reach. I don't think I've ever played the single-player campaigns..
That's fair. A lot of my friends are the same way and never touch the single player campaigns on these shooters (even though I've heard Halo has pretty good campaign stories).
It's just not something that appeals to me personally. For me, an immersive story comes first, and multiplayer comes second. For example, I probably put more time into Dark Souls on the 360 then any other game since Final Fantasy VII. And even though I LOVED pvp, I didn't even touch it until i exhausted my single player play.
I don't hate shooters, it just kinda takes a special one to peak my interest these days. I loved the immersive world of Far Cry 3 and the level grinding/loot whoring of Borderlands.
Honestly, the hype surrounding Titanfall makes me feel good about my decision to switch back to Sony this generation. Last generation, I found myself jealous over the story-driven exclusives Sony was offering while MS exclusives were mostly limited to multiplayer shooters like GOW and Halo.
At this point, I'm stuck in my ways. I love RPGS and story driven epics, with the occasional sports sim thrown in. Games like Dark Souls PVP and Borderlands co-op are opening me up to multi-player a bit, and I think I'll try it with Destiny, The Division, and finally try some MMO's coming out on PS4 this year.