Anything with the combo of peanut butter & chocolate is bi-winning. Reese's Peanut Butter Cups.
Butterfinger's a runner up.
I used to love sour stuff a lot more, apple/peach rings, sour gummy worms, Warheads and Cry Babies (sour gumballs).
I haven't had any candy in probably 2 years, now not counting having something in ice cream or a blizzard. And now that I think about it I'm not really sure why. Though I'd have to go with anything chocolate.