If you’re either a literary geek or a regular geek, io9 has an excellent piece on Tolkien’s view of dragons.
Dragons are a curiosity to me, mostly because they’re another of those things that, for no apparent reason, can be found across cultures. Europeans and Asians both have ample tales of dragons. Even Australian aborigines tell of a creature that could fairly be considered a dragon. It’s enough to make you wonder if some dinosaurs managed to hang around into human pre-history long enough to inspire a few legends.
Even more interesting, European dragons were not always the giant lizards they are today. They used to be much more serpentine-very much like Chinese dragons. One distinction does hold strong, though: Asian dragons are benevolent; European dragons are evil. Smaug, obviously, is a European dragon.