Philadelphia Art Museum – Arms and Armor
This is one of larger Art museums in the east coast, while not as comprehensive as say the Metropolitan Museum of Art in NYC, still worth a visit if you are in the area.
Specifically for military buffs interested in Medieval Arms and Armor, their collection is very good and is about half the size of that at the NYC MMOA Good collection of swords helmets, and personal armor. And if you wanted to expand your interest – good European Impressionist painting also.