5. Space Merchants - Frederik Pohl. This is one story that could perfectly have been written this year (as long as you overlook some of the props in the scenes), because it reflects two concerns of today's society: rampant environmental destruction on behalf of industrial growth, and the power of marketing and advertising to subvert men's wills (well not as much as that but pretty close). It's interesting to see how some social concerns don't fade but just change in appearance and packaging; this novel is a must read for conspiracy theorists.
I hope you enjoy this short list and that it will help you find some of the landmark political novels in science fiction history. And if you buy one of the books from the links provided here I will be eternally grateful to you. Oh and if you have anything to add (be it praise or criticism) please be sure to leave it in the comments.