I came out of a cave after barely surviving it and felt pretty awesome (this was back when I was level 10 or something). Heard a roar and looked to my right just in time to see the wall of flame come rushing down the hill. Made a mad dash for the nearest Imperial camp. Passed some thugs who had been hired to murder me--didn't realize this until I found the note on their corpses--and joined up with the Imperials. It was rather amusing watching everyone drop their grudges and focus on the dragon. Of course, as soon as it was dead, the one remaining thug decided to try and fulfill his contract. A pity. To survive a battle with a dragon, fighting alongside the hero of Skyrim, only to die in one hit from my blade. Attacking with one a few hit points left is never a good idea.
Of course, now my character is level 53. A dragon isn't so much a threat as it is, "Hm, well I DO need more gold..."