I don't know about private dorms, but if you go with the school's dorms go with something like Sellery (or Chadbourne! that's where I'm living now). Last year I lived in Ogg and it sucked. Maybe if I was going into it with friends it would have been great (the walk in closets were beautiful...). The problem you get with the really nice places (which could be a problem in private too) is that if the rooms are too nice people stay in their rooms. I tried hanging out in the den but it was always empty
And due to fire codes, buildings built recently have to have doors that close automatically. From what I've heard from friends, it seems like the classic dorms are the best for meeting people. Chadbourne might be the best of both for you next year, because although the rooms are staying the same size, they're rennovating it over the summer. All rooms will have controllable AC/heat (though mine does now) and they're adding a kitchen to every floor, and re-doing the elevators. Chadbourne is also in the best location of all the dorms, right on the bottom of Bascom Hill. But you get the same idea in Sellery and Witte.