That's me above, with a piece of paper serving as my buck teeth. On the basis of the photo above I'd say that buck teeth make you look younger, and that doesn't hurt. Buck teeth make you appear idealistic as well, another unexpected benefit.
Of course there's no denying that buck teeth make you look stupid...or do they? The Nutty Proffessor looks stupid but his fake buck teeth are superimposed on a normal dental template and are obvious symbols for comedy.
Real buck teeth occur on on a forward thrusting palette, and in context, don't look so bad. Take a look at the kid above. His buck teeth look good to me and if I was his dad I might consider doing without braces. Or maybe I wouldn't, I don't know.
Why is this girl (above) said to have "The Ugly Betty" look? She looks fine to me. Does she really need braces?
Sometimes buck teeth are blamed when the real culprit is a weak chin. Buck teeth are fine for my taste, and so are weak chins, but the combination of the two is a sure visual symbol for stupidity, regardless of how intelligent the person may really be. I have both, but I take it in stride. There's no use worrying about what you can't change. I wouldn't look like me with a strong chin, and I wouldn't give up my buck teeth for anything.
This (above) is my species. We evolved overbite and buck teeth to better masticate the gnarly fruits and bark to be found on high jungle branches. If a comet strikes the Earth again bark biters like us will carry on the human genotype. We stand ready to give our all for the continuation of human life on our planet!*
* OK, I made up that stuff about high branches but there must be some advantage to buck teeth. I have noticed that we tend to be sexier. You never see buck-toothed bachleors.