The shelf life of most milk chocolate is one year; for most dark chocolate, it's two years. Chocolate keeps best between 65° and 70° F, away from direct sunlight, and protected from moisture. When refrigerating or freezing chocolate, make sure it is sealed in an airtight container-refrigerators are very humid. Always thaw frozen chocolate in the refrigerator; if it goes straight from the freezer to room temperature, condensation will form and alter the appearance and texture. Always allow chilled chocolate to come to room temperature before enjoying it; cold chocolate doesn't melt or disperse flavor as nicely.
But I've always heard NOT to store chocolate in the fridge. Why are you telling me I should?
Well, ideally, you shouldn't. You'd store at room temperature-if your room temperature was around 65°- 70° F. It is the middle of the Summer, and /or you don't have air conditioning, that's not the case. Storing chocolate in the fridge or freezer will keep the heat from melting your chocolate and running the temper (that whitish coating on melted and re-hardened chocolate is the cocoa butter coming to the surface).
Generally, the reason you're told to keep chocolate in the fridge is either because a) it doesn't have a very long shelf life or b) that, when you take it out of the fridge, condensation will form and cause sugar bloom. (Sugar bloom looks like dull blotches and spots that are rough to the touch; chocolate that is sugar bloomed cannot be re-tempered. Don't worry, though-it can still be used in baking, sauces, and pretty much everything else.)
As for the condensation issue, the slower you let chocolate come to room temperature, the lower the chance of condensation forming. If you have chocolate in the fridge, and it's 80 degrees out, I'd recommend wrapping the already wrapped chocolate in a towel, or some other insulating barrier; this will disperse the chill from the chocolate more slowly, and minimize condensation