It took me forever to get past bombadil (literally, the first chunk of the book took me 6 months to read through. Nothing takes that long). However, it was interesting after that. I read Return of the King over an 8 hour period, it was that tense.
The Silmarillion was great imo, cause it was the bible with less crap. Just lots of wars, badguys, goodguys, days saved, epic battles, etc. Fun fun.
I also have the Unfinished Tales, which are important because the partial hobbit rewrite contained in it is heavily used by the new hobbit films. To the point that the introductory scene from the second film is line for line pulled from the Unfinished Tales.