Lately I've been having a craving for anything chocolate with Mexican influences - drinks, cookies, truffles...anything. But in looking at a lot of recipes, I've become confused over which spices to add. Cinnamon is easy enough, but some recipes call for ground red pepper, some for black pepper, some for cayenne pepper, some for chili powder, and some for any combination of the above. Does one really taste different than another, or are they interchangeable? And if there are discernable taste differences, is one better than the other?