With the Old Breed, by E. B. Sledge. My recommendation to anyone, if they are to read only one book in their lives about warfare, this should be it.
Now in no particular order:
Masters of the Air, by Miller. Covers the whole gamut from strategic considerations down to individual pilot stories about the 8th AF bomber guys.
Top Guns, by Foss and Brennan. Interesting stories from various US aces.
Samurai, by Sakai. The biography of Saburo Sakai, one of Japan's top aces.
Last Stand of the Tin Can Sailors, by Hornfischer. Awesomely detailed story of Leyte Gulf naval battle.
Neptune's Inferno, by Hornfischer. Story of the Guadalcanal campaign, which was a very evenly fought bunch of battles with surface-ship combat, carrier combat, air combat, and ground combat.
The Bravest Man, by Tuohy. Story of Dick O'Kane and the USS Tang submarine.
No Simple Victory, by Davies. A great history of WWII with aspects not known by most Americans.
America's Hundred Thousand, by Dean. Great details on all the major US WWII fighters.
The Lockheed P-38 Lighting, by Bodie. Excellent, very detailed, and entertaining history of the P-38.
And because I can't stop at just 10:
Zemke's Wolfpack, by Freeman. Great stories of Hub Zemke, the Wolfpack, and P-47's.
The First and the Last, by Galland.
There are a lot more.
