In your opinion, which specialty has the smartest docs? The nicest? The least nice? My vote: smartest = pathology; nicest = pediatrics; least nice = it's a tie: endocrinology and vascular surgery.

Value judgments. Being human, physicians have varying personalities ("niceness") and all have intelligence or they wouldn't be in medicine. People have value judgments, though. For instance, many physicians told me i was "too smart" to go into psychiatry. Should we make similar judgments about 43 year old men from athens ga -- saying they're not as nice or as smart as women from atlanta? I think not. :-).
Stereotyping. Stereotyping doctors is of no more use than stereotyping any other group of people. It is more important for you and your doctor to have a good rapport.
Some trends but... Interesting question. I agree with dr. Singh that stereotyping is often counterproductive, but certain personalities seem drawn to certain specialties. Most pediatricians are really nice, but family ; holistic docs also tend to be esp. Nice. Pathologists are often quite bright; many pulmonologists are very smart. Jocks often became orthopedists. No idea re: least nice; i hope most docs are nice!
Interesting. My vote is that the best doctor is the one who looks you straight in the eye, is attentive and listens carefully to your complaints. Being smart is part of the dna in a physician but being a real physician incorporates what i listed above.
I know this asks. my "opinion" so maybe I should just give it ;) But, really, I don't think a generalization could be accurate. A Univ of Wisconsin study didn't break it down by specialty, but found docs overall to have highest IQ of 56 professions, so just generally a high scoring group. A study of Emotional Intelligence by Mass General found no difference between pediatric, pathology, and surgery residents.