I use 1st for archery in cramped spaces, and to pick up and place objects. For everything else, 3rd person. I hate the few scripted scenes that force you to be in 1st person. It feels like I can't see what's happening!
But I started at the other end of the scale, Only used 1st for my first two and most of my third playthroughs, and hated when horseback riding or werewolf transformations forced me into 3rd... Then I started to take screenshots, and the more screenshots I took, the more I played in 3rd instead of 1st.