What's Your Favorite Military Science Fiction Novel?

We talked about a couple of the classics of military SF, including Enders Game by Orson Scott Card and Starship Troopers by Robert Heinlein. And so I guess I'd like to start out just talking about what are some prominent examples of fantasy and science fiction that feature soldiers. But I think of those as sort of being the top tier. A lot of the authors in my anthology armored or former military officers and right military SF.