My little guy is 18 months now. I also loved the books - especially the signed copies from close family. He'll have their sweet thoughts for years to come!
He was also at a new stage of play by one year. I think he enjoyed the Fisher Price Learn and Grow series the most - he still loves his tool bench and many others! They are also rather economical for the size of toy - averaging $15-$20. Many people asked me directly what he liked or his clothing size. Take a hint from the invite as well. We had an Elmo party because he loved "Sesame Beginnings" at the time ...our invite was very Elmo heavy! Hope this helps!