I would have said Twix until I got a box of them recently: not quite as good as I remembered.
Snickers or Milky Way are probably my favorites at the moment.
For non-chocolate candy, I like Airheads and Sour Patch Kids. I'm not much of a candy person though, especially if it's not chocolate.
All candy must be full size. That fun size BS is too small to impart the proper texture and ingredient ratio in each bite.