The Hobbit will be giving more new than Avengers. Aside from Bilbo, Gandalf, Legolas and Galadriel all characters are new.
Avengers featured all characters we've seen on-screen before, even the villain, only new character was that Maria Hill woman
I love LOTR and Hobbit as well. Read them when I was 12, never thought they would get made as movies, at least not made well. When I saw that first trailer, of the Fellowship walking up over the Hill, I had a tear in my eye. I was incredibly excited.
That being said, I just don't see this movie making as much as Avengers. Before Avengers came out, I knew it would be huge, comic book fans are rabid for this. Think about it, you have Thor, Ironman, Hulk, and Captain America fans all dying to see this one movie. It is self contained (i.e. no necessary sequels) runs about 2 hours, and is non-stop action playing during the summer when every kid between 4 and 64 would see it numerous times.
As much of a following that LOTR and JRR Tolkien have, it just cant compare.
Don't get me wrong, it will do huge business, and deserves to, but it just wont make it to surpass Avengers Box Office.
1.2 Billion I say, maybe 1.3. I could be wrong, but I dont think I am. The only real wild card in this is if HFR is a huge hit and everybody feels they must see the movie in HFR, much like people had to see Avatar in 3D.