Tolkien has been a big part of my life since my dad read LOTR to me when I was a boy. LOTR and The Hobbit are both very dear to me, and like most Tolkien fans I like to read them on a yearly basis.
I loved the LOTR movies and thought for the most part they did an excellent job of bringing the books to the big screen. I can understand most of the changes they made, Tom Bombadil was never going to be accepted by most people for example. I saw an interview with one of the script writers where she said that they prefered to think of these chapters (The old forest in that example, and the Scouring of the Shire for another) as stories left untold.
In The Hobbit movie they seem to have done the reverse and expanded on 'stories left untold'. Gundabad for example gets a one line mention in the book, as does a brief mention of the White council dealing with the 'Necromancer' in Mirkwood. Bit of a money spinner perhaps but I'm looking forward to seeing what they do with it.
All that said, I still think enjoyed the FOTR a lot more than The Hobbit an unexpected journey as a first instalment. Mainly because of the overuse of CGI in the Hobbit, the beautiful minatures they made for the LOTR made for much better watching.