Of my modest library, Neukirch's Algebraic Number Theory is easily my favorite. It's approach to class field theory avoids cohomology, so a student without a heavy algebra background can use it as a second course in algebraic number theory. I appreciate the third chapter as a down-to-Earth glimpse of Arakelov theory as well. Certain sections, exercises, and remarks hint at deep connections between number theory and algebraic K-theory. And of course Neukirch's style and organization is simply delightful.