A fresh-from-the-freezer Reece Peanut Butter Cup
Mars and Snickers bars "available chilled" at a local sporting event
I like my chocolate ice cold. There's something I just enjoy about the crisp, crunchy snap of chocolate fresh from the fridge (or occasionally the freezer). Obviously, not all chocolate does cold well. The best candidates I've found for the fridge are things like Reece Peanut Butter Cups or Bars (but not Pieces), Kit Kat, Green and Black's White Chocolate and other things that are covered with or made entirely of relatively thin milk or white chocolate. I'm also told that freezing York Peppermint patties (but apparently not Pep) yields an amazingly refreshing treat. Dark chocolate and thicker milk chocolate can also be chilled as long as it's done carefully as they can become quite brittle. Even some chocolate bar makers are merchandising their products cold (see banner above for Mars and Snickers "available chilled" at BMO Field).
Although some say that refrigerating chocolate can result in so-called "chocolate bloom", I've rarely encountered this problem myself and tend to believe it's more the result of a quality issues with the chocolate. So if you haven't already, I recommend trying your favourite chocolate straight from the fridge, especially during the summer when chocolate is prone to melting.