The New Turing Omnibus http://ecx.images-amazon.com/images/I/51HlYd-%2BRwL._BO2,204,203,200_PIsitb-sticker-arrow-click,TopRight,35,-76_AA300_SH20_OU01_.jpg
Really good book. Has a high-level taste of the most important areas of computer science. Yes, CS != programming, but this is still useful to every programmer.