OK, now for my actual response. Some underrated beers. Or maybe, "great beers you may have never heard of".
Sam Adam's Black Lager and Ale are both good and I don't see them around much. In general, as a largely ale drinker, the Sam Adam's Boston Lager is good (but that's not underrated!).
Great Divide (colorado) Titan IPA and Yeti Porter. These may not be underrated out there, but you don't see much of their stuff out East. The Titan IPA is solid and somewhat balanced. The Yeti is intense as shit. I've only had it one night on draft but my asshole friend decided we were getting a pitcher of it and we had to drink it in record time because his girlfriend was falling asleep. I'd like to enjoy it more slowly.
The Great Lakes Brewing Co. has a couple of very tasty entries that have popped up in this area lately. They're not really new, but I had never heard of them before. Their Commodore Perry (an IPA) is wonderful, and if you're more into lagers then give their Eliot Ness a shot.