As a child, I was categorically opposed to dark chocolate and would only consume the milk variety. Thank Hershey for this insane predilection because their "Special Dark" was only type of dark chocolate I had tried and therefore I assumed all variants were just as waxy. (Note: In the past decade, Hershey has revamped its Special Dark recipe and now it is quite palatable.)
For this reason, I was late to discover that dark chocolate hot fudge (not to be confused with chocolate syrup) is absolutely wonderful on sundaes. The darker, the bitterer, the better.
Yesterday, I stumbled upon Smucker's Dark Chocolate Topping, which was more than decent and less than transcendent in flavor. Appropriate, I guess, for a Monday.
The best dark chocolate fudge I ever tasted was on a sundae from Picco in Boston. They used Scharffen-Berger to make their sauce and God-I-wish-I-knew what else.