Abel and Bernanke; comprehensive and thorough; the only textbook I( bradford delong) have studied closely that is comprehensive enough to serve as a true reference; has perhaps the greatest information content of any I have studied in depth--but it is not an easy read, for reasons of style and density.
Blanchard; a tour through how Olivier Blanchard thinks about macroeconomic issues; master this book and you have a comprehensive grasp of how one of our very best macroeconomists thinks about the world--but it is a tough and demanding book, one that I have been scared to give it to any except my very best undergraduates.
Mankiw; by far the clearest of any of the books; Greg Mankiw is the master of exposition, for there is no one who can better explain economic concepts to students--but too large a proportion of the book is hard to apply to real-world economies.