One thing that tipped Dan and I off to the fact that we birthed the übermensch is that he is pretty close to being literate at 5 1/2 months. We started reading to him at about 2 months (because he was colicky and awake CONSTANTLY and my God we tried everything), and he paid WAY more attention than we expected him to. It has been really neat to see him focus... He looks at the type, and then the pictures, and sometimes right at your face while you read. He gives a big smile and is usually quiet while you're reading (which is not typical) and he enjoys 3 or 4 books in a row.
He has some normal faves like The Very Hungry Caterpillar and The Rooster Struts. He also likes the Nancy Tillman books Wherever You Are My Love Will Find You and On The Night You Were Born, which are beautifully illustrated and occasionally make me cry while reading them. His favorite book, however, was a bit of a surprise to me, and it makes me very, very happy. Every time I put him in his seat and show him the cover, he lights up and kicks his legs. It's called We Need a Horse, and it's eloquent, simple, fun and beautiful. I bought it years ago from a McSweeney's sale and only really flipped through it before putting it on our children's book shelf. It follows a horse as it finds it's purpose and place in the world, and it is written in a way that is reassuring and uplifting, touching on very important concepts in very few pages. We are all here for a reason, it's ok to just be, and you can love people FOR their quirks instead of despite them.
I highly recommend. And good news: it's still available on the McSweeney's site:)