all of David Weber's Honor Harrington novels, and the Prince Roger series by David Weber and John Ringo.
A big +1 on that. David Weber's Honor Harrington series is one of my all time favorites. It's exceptionally well written, good characters, interesting story. Plus, the main characters favorite weapon, in a time of space ships and high tech weapons, is a 1911 .45ACP. What's not to like?
Tom Clancy's early books are also quite good. I recommend "A Hunt For Red October", "Patriot Games", and "Clear and Present Danger" with out reservation. His newest books are getting pretty bad.
Non-fiction, Carl Sandburg's biography of Lincoln ("Lincoln: The Prarie Years and the War Years") and Marshal de Bruhl's biography of Sam Houston ("Sword of San Jacinto").
For a great read on the road, try Jim Butcher's series about the wizard Harry Dresden. Really well written, taut and entertaining.
Here's a second on Jim Butcher. I've read the entire Dresden series and thoroughly enjoyed each of the books.