I don't want something extremely challenging intellectually—what I want is something intellectually expanding that can be read in huge chunks (similar to fiction, although I'm generally not into fiction). That's exactly what I loved GEB for.
Have you read any other Hofstadter books? I know he says that subsequent books of his express the themes of GEB even better than GEB itself did, but I'm afraid they might end up being repetitive.
I've sought out books about the subjects I love: decidability, completeness, theory of computation, statistics, automata theory, language/compiler design, etc. but they've all been too rigorous to read before sleep. For those of you that loved GEB, what else do you love?