Enough said by me... We both know each other's favorite books, and that is why we came here is it not?
But it's just too easy to say "LOTR is my favorite," I guess. I think in that case "favorite" has to be qualified.
To tell the truth, I don't enjoy Tolkien's work because he was an outstanding writer--he was good, but he was too steeped in the cadence and strange turn-of-phrase of the Middle English of which he was a scholar. Rather, I enjoy it so much because of the STORY. But there isn't much beyond the story, Tolkien himself repeatedly said he was NOT writing an allegory, or an autobiography, or anything of the sort. He simply wanted to try his hand at crafting something along the line of a Nordic saga. He wanted to create a mythology.
As LITERATURE in the fullest sense of the word, LOTR is just "above average." The STORY is wonderful, but the prose is of a singular, even crude style. I don't mind that--I even enjoy it--but it is idiosyncratic in the same way as, say, Conan Doyle's "Sherlock Holmes" series. In that case, too, the STORIES were fabulous and keep you riveted, but the style of writing is quite singular. It doesn't attempt to rise far above the story, to express much more than the simple telling of the tale.
That said, I put "A Study in Scarlet" on my list, but because this was Conan Doyle's first book, and so more "fresh" than his other works. In fact, for the very same reason, I would actually rate The Hobbit above LOTR.
Most scholars will tell you the best novel in the English language in the Twentieth Century was James Joyce's "Ulysses." That kind of lets you know where we're headed, here.