My vote went for dark chocolate, over 80%, though what I normally buy is 72% because that is what is the cheapest
(really big chocolate bar for four dollars).
I tried the chili chocolate that Loc mentioned already. It is actually good. I recommend it. As for me though, I can't buy that stuff on a regular basis because it's usually over three dollars for a 100 gram bar where I live. That's a little too much money to be anything other than a rare treat.
The first time I ever ate chocolate that was over 90% cocoa, I made the mistake of eating it too fast and almost gagged. That stuff will make you thirsty.
I also like white chocolate and milk chocolate and well... any kind of chocolate, with a preference for real ingredients (like cocoa and whole milk) over chemicals (words I probably can't even pronounce).