How long can you keep chocolate in the freezer?
My wife is obsessed with Milka, and last time we were in Germany, she threw out all my clothes in order to fill an entire suitcase with it. When we got it home, it got piled in the freezer (not the freezer-in-the-garage-which-is-seldom-opened, but the regular one where we keep ice cream and frosty beer mugs). Took us more than 4 years to finish it. The last bit was effectively identical to the first. No noticeable change in the product.

Given that quality chocolate has no water (which is the primary freezer-spoilage agent), I'd say it would keep effectively indefinitely. If you're talking about candy bars which contain other ingredients, it may vary.

Generally though, things don't go "bad" in the freezer. They can get brutally freezer burned and disgusting, but there is no safety issue, as long as the food remains frozen. I once made a pie out of a quart of blackberries I found buried in the ice in an old-style freezer chest. Estimated age was on the order of twenty years, but they'd been preserved by the encroaching frost. Pie was delicious.