I was finishing the quest to transcribing the Lexicon and I came across Blackreath, can I just say WOW!!!!! I have seen very impressive scenery, especially the clear night sky, but Blackreath just blew me away. The floating Jellyfish were cool and the fortress was fun to explore, although it was so big I eventually got tired of sneaking around and offing the Falmer and their flunkies but they had a lot of gold so that was good. I eventually finished that part of the quest and now am looking around for Elves to kill and take their blood. This is my first Elder Scrolls game and I am loving it.
P.S. has anyone fully explored the Silent City Catacombs? I was wondering if there anything down there worth going back for eventually.