The only coffee I remember having that tasted chocolatey was an Indonesian blend.
Yeah, it's rare. Turns out, it's the first casualty of oxidation. There's about a 5-7 day window after roasting before the beans lose their taste and develop off-flavors. And, evidently, vacuum sealing won't prevent it, since there is enough oxygen trapped within the bean to cause it. This is what drove me to roast my own beans. By the time beans make it to the shelves at the supermarket or coffee shop, they're already past their due date and taste nasty.