FYI, in case any of you end up with the same issue.

Not sure why (or if it's normal or not), but last night after converting a polygon to subd, the shading dissappeared and went to wireframe (perspective view). Pressing 1-7 had no effect. Since I had the object in isolated view in the side view pane, I decided to unisolate it and when I did, my shading came back in my persepective view.

I've never had this problem before. I think it might be due to the fact that all my Rotate/Scale/Transform settings were locked. I've unlocked them but havn't tried to recreate problem yet. I'm using 8.5 Unlimited.