I really think A Series of Unfortunate Events is so worth a read as an adult. It's fun, meta, plays with its presentation of words on a page. And towards the end the story dovetails into allegory and metaphor, which is a lot more than I bargained for in a children's book.
Also, finding all the little literary references as an adult is fun! I definitely didn't pick up on, like, anything when I was a kid, but there are quite a few.