Pre-ordered: The Annotated Turing
So many of the books (and music, and TV, and..) I love sit in that sweet spot where you either can't wait to get your hands on it; or you can't imagine wanting to bother with it at all. Alan Turing generally hits a broader audience, but his computability paper (PDF)? And a book walking you through the same? Right on the money.
Computer geekery? Check. Math geekery? Check. Written by Charles Petzold? Check.
Looking forward to that email in May - "Your Amazon.com order has shipped... The Annotated Turing: A Guided Tour Through Alan Turing's Historic Paper on Computability and the Turing Machine"