I know I've mentioned it on here before, but I'm just going to give another plug to the Backlisted podcast. Over what now runs to more than 120 episodes, they've discussed a huge variety of books (mainly novels, although they've also touched on poetry and biography). Generally they try to shine a light on lesser-known if not downright obscure books, but they've also covered more mainstream works, too. Although, one of the pleasures of the podcast is that you usually end up realising the the Book being discussed is not exactly what you thought it was, anyway.