+1 on Dan Carlin pod casts and another +1 on the Teaching Company/The Great Courses audio books. In addition to David McCullough's 1776 mentioned above, The Great Bridge and John Adams was excellent. There are a whole slew of audio books on WWII, the Korean War that are excellent. Here are a few:
With the Old Breed: At Peleliu and Okinawa
Band of Brothers
Helmet for My Pillow: From Parris Island to the Pacific, A Marine Tells His Story
Retribution
Matterhorn
We Were Soldiers Once...and Young
The Last Stand of the Tin Can Sailors
Neptune's Inferno: The U.S. Navy at Guadalcanal
The Last Stand of Fox Company
The Coldest Winter: America and the Korean War
The Guns of August: The Pulitzer Prize-Winning Classic About the Outbreak of World War I
Killer Angles by Michael Shaara and any of Civil War and WWII books by his son Jeff Shaara.
The following three books by Rick Atkinson:
An Army at Dawn: The War in North Africa, 1942-1943
The Day of Battle: The War in Sicily and Italy, 1943-1944
The Guns at Last Light: The War in Western Europe, 1944-1945
The following three by Simon Winchester:
Krakatoa: The Day the World Exploded: August 27, 1883
Atlantic: Great Sea Battles, Heroic Discoveries, Titanic Storms, and a Vast Ocean of a Million Stories
Pacific: Silicon Chips and Surfboards, Coral Reefs and Atom Bombs, Brutal Dictators, Fading Empires, and the Coming Collision of the World's Superpowers (listening to this one right now)
There are many more that I have listened to over the years (over a hundred).