Why not the 54 bore (.442 cal.) Adams-Beaumont revolver as a top ten pick? It was one of the most stylish guns of it's era - or any era, and was the first true double-action revolver in the world. It was adopted by the British Army in 1856 and served the Brits in that capacity until at least 1884. Some Union and Confederate officers carried Adams -Beaumonts during the American Civil War. The one pictured in the attached hyperlink is a percussion cap revolver although many of the percussion cap models were later converted to fire rimfire cartridges.
http://upload.wikimedia.org/wikipedia/commons/3/34/Beaumont_Adams.JPG
http://upload.wikimedia.org/wikipedia/commons/3/34/Beaumont_Adams.JPG