Because no one ever grabs it, I get the hunting rifle to balance the team out. Because I use it so much, I've become expert at sniping out special infected from afar. I usually get most smoker/hunter/boomer kills this way.
I'm the "mow zombies down" kind of person when it comes to L4D, which is surprising since in everything else, I'm better of a sniper (problem is, when I play, someone else always picks up the hunting rifle first and then starts picking off zombies, so I have no choice but to go for non-ranged weapon). Still, I like being able to fire all ten shells within six seconds.
And the auto-shotgun has saved me many times against witches and tanks. I pump them full of lead.