Chart of survey of satisfaction by medicine specialization in United States

A survey of physicians in the United States came to the result that dermatologists are most satisfied with their choice of specialty followed by radiologists, oncologists, plastic surgeons, and gastroenterologists. In contrast, primary care physicians were the least satisfied, followed by nephrologists, obstetricians/gynecologists, and pulmonologists. Surveys have also revealed high levels of depression among medical students (25 - 30%) as well as among physicians in training (22 - 43%), which for many specialties, continue into regular practice.[14][15]

Reference 1: Overall satisfaction[13], Feeling of enough compensation[13] and Would have chosen same specialty again[13].

Reference 2: Dermatologist, Radiologist, Oncologist, Gastroenterologist, Ophthalmologist, Infectious disease/HIV physician, Plastic surgeon, Anesthesiologist, Orthopedic surgeon, Psychiatrist, Rheumatologist, Podiatrist, Emergency medicine physician, Urologist, Cardiologist, Pediatrician, Diabetes specialist/Endocrinologist, Neurologist, General surgeon, Nephrologist, Obstetrician/Gynecologist, Pulmonologist and Primary care physician.

Source: http://en.wikipedia.org/wiki/Medical_speciality