A common question: what do you read?
A rare question: what do you re-read?
I read books that I expect to be good.
I re-read books that I know to be excellent.
I read new books to be introduced to new thoughts.
I re-read books to remember the old thoughts.
I've heard it said that you can tell a lot about a man by what he reads.
I would simply add that you can tell even more about him by what he re-reads.