rum? That sounds odd. I do like an old fashioned if there isn't too much sugar in it, but i'm more of a manhattan drinker.
I had it at a very, very fancy pants bar in Frankfurt called Jimmy's. The waiter was in a suit and tie, the regulars were smoking cigars, the women were all in formal gowns or evening dresses, and there was a guy playing a mini grand piano.
I asked the bartender, "What's your favorite drink right now?" He said, "Probably a rum old-fashioned." I ordered one, watched him make it with perfect showmanship, and then drank one of the most delicious, harmonious cocktails in my life.
I've ordered it twice here in the USA. The first time, it was pretty good. The second time, the bartender admitted he had never heard of a rum old-fashioned, and the flavors simply did not cohere. So you need a bartender who knows and likes the drink. Tall order, I guess.