If I’m put on the spot about my favourite book (for example, here), I almost always go for The Count of Monte Cristo. It’s very long, it simultaneously plays to and undercuts Gothic tropes, it has a ton of moral ambiguity, and there is a lot of early nineteenth century opera and a lesbian elopement.
Stephen Fry, regrettably, omits the operatic lesbians, but I really can’t complain about such an affectionate, funny, adaptation as The Stars’ Tennis Balls. He isn’t just thinking of The Count of Monte Cristo, he’s thinking of it with real fondness.
I’ve got a rather long (and probably you-had-to-be-there) anecdote in which I tried to explain one of the jokes to my brother in the driving rain on the Camino Inglés. You might see it in a month or so, when I’ve got round to writing up the journey.