Having read LOTR many, many times before I ever started trying to read Pratchett, I can't read Pratchett. That's not a slam at Sir Terry; I'd just internalized Tolkien so much that it was beyond my ability to properly appreciate him.
If you haven't tried it, Small Gods is frequently recommended as a standalone, and it's very far in subject matter from the early tolkien-parody rincewind/guards books.
If you haven't tried it, Small Gods is frequently recommended as a standalone, and it's very far in subject matter from the early tolkien-parody rincewind/guards books.