My favourite outdoor location is Archwind point. Today is the first time I've been there and I thought it looked great. I had great fun fighting 10 skeletons and a couple of draugr death overlords on Legendary difficulty.
I took a couple of pictures of it.
http://i.imgur.com/aMR2iin.jpg I set the map marker on the start of the ruin for anyone who doesn't know how to get there.
http://i.imgur.com/u9v4z5i.jpg