I'm reading The Hobbit for the first time in years and years, and I am finding that there is a lot of detail I do not remember. 

When I was in Taiwan this spring, I brought my wife a Mandarin version of the Hobbit.  When we were in Austria and Poland, this summer, she bought additional foreign language versions and has been sitting, comparing them sentence by sentence witht eh English version.  So the fact that she has been reading, and that Peter Jackson et al are developing two Hobbit movies, motivated me to begin my own reread.

I didn't remember HOW Bilbo got into Gollum's cave.  I didn't remember how different elves are in The Hobbit compared to LOTR.  And I'm not done yet, so I don't know what else I didn't remember.

I can see, however, the naturation of Tolkien's storytelling style and of his vision of Middle Earth.  It is really quite a different place in The Hobbit.