I have a huge sweet tooth so I've tried a lot of different candy bars. My favorite used to be Three Musketeers, but these days (and for a long time now) it's been Crunch. I love the rice bits and the crunch it has, but honestly it's the flavor and sweetness of the chocolate itself that I can't get over. It's a really good recipe.
I go through different phases with candy bars, ( for the longest time it was Sinckers ) but I think my main stay is but Kit-Kats. I don't know why Kit-Kats go great with coffee.