I'm not a collector, but I like using stamps that have meaning to me. The recent architecture stamps include a house I once housesat in. Today I went to the post office and when I saw stamps honoring U.S. scientists, I bought a set. I'm very amused by the selection of scientists. That there is a token woman is no suprise: Barbara McClintock. The others are Josiah Willard Gibbs, John von Neumann, and Richard Feynman. I'm surprised the Joseph Henry papers folks didn't get Joseph Henry in as the token 19th century scientist. What did it take to be an American scientist? von Neumann was not born in the United States, but he was apparently counted as more American than Einstein? Apparently there was a letter writing campaign to get Feynman on a stamp, so that may be the origin of this.