I can shed some light into this for you'all. First of all, I am a second year anesthesia resident. Just so you know where I am coming from. OK, lets get to some business.
Most specialties in medicine can work 9-5 with cut in pay. Some, however, exceed others. The aforementioned ROAD specialties are very popular (Radiology, Optho, Anesthesiology, Dermatology). You can make a good living in these specialties with very little work (35-45 hrs/wk). I'll give example of anesthesia since i know the most about it.
Anesthesia: if you want work 40 hrs/wk, you can with surgery centers. There are multiple surgery centers popping up everyday as we speak. you would bring home around 250K depending on the practice. some pay for malpractice while others don't. some offer partnership, some donot. most have hours from 7am to 3 pm. few have 9am to 5 pm. most surgery centers you would be supervising nurse anesthetists. some you would be doing everything. if you want to be clinically inclined, you can do everything; if you don't, then you can have an "administrator" type of job and just chill out. Now here comes the hard part; in order to get to this, you have to go through residency. In anesthesiology, residency averages 60-65 hrs/wk with taking call around once a week with going home at 7 am post call. so unlike dentistry, you have to suck it up and go through residency. In the plus side, if you work 55 hrs/wk (1 call every 7-10 days) your income goes up significantly. Partnership in anesthesia is usally 2 yrs after residency. Partners are averaging around 300-350K with 401K retirment plans, malpractice paid, etc in these practices. Hope this helps.