We have a collection of various wooden block sets, but these Uncle Goose numbers are my favorite lately.  We keep them in a big antique yellow ware bowl so they are easy for the kids to get to and clean up.  I love the colors and the carved details and their weight.  This set also has a rocket ship, skyscraper and circus on its sides.  There is something perfect and timeless about a child playing with blocks.  There are theories that block play leads to better understanding of language structure and spatial relations.  But I love to watch the girls imagine worlds and structures without bounds as they stack blocks.