Lord of the Rings is a fabulous book, although slow starting. The Hobbit is entertaining if a little childish and clearly intended to be read out rather than simply read.
The Silmarilion, the Books of Lost Tales, Unfinished Tales and all of Christophers shameless cash-ins are bordering on the unreadable.
The Bible has it's moments, certainly (I always rather enjoyed
Ecclesiastes) but mostly it's a turgid dirge.