The reason there's so many substitutes is that the original contents are no longer available in their original recipes. The original vesper called for Gordons a

The reason there's so many substitutes is that the original contents are no longer available in their original recipes. The original vesper called for Gordons and didn't specify which vodka, so you have to improvise. As for drinking 'actual Martinis' there's no such thing as an actual Martini. There's plenty of stories as to the origin, ranging from the Mexican gold digger in Martinez to the bar in New York that put gin in with Martini Rosso in the late 19th century. I tend to follow the Knickerbocker Hotel 1911 recipe for classic Martinis, which I make often but a well mixed Vesper is an incredible drink, and something most of the people here are unlikely to have tried. It's the closest I can imagine to an actual pan-galactic gargleblaster.