Books meant to be annotated

I'm currently reading Nabokov's Pale Fire (and I'm loving it) and this is the first book I ever really felt like annotating. I feel like annotating it makes the reading experience even better.

That being said, do you know of books that are meant to be annotated? Or books that feel like they should be? I think you get the gist

Also feel free to suggest books that aren't specifically meant to be annotated but you felt like you had to if you know what I mean