I commonly get asked the question, "How much does a physician in specialty X make?" The question is just as easy to answer as "What is the cure for AIDS?". You can't easily compare salaries in medicine because some docs work 30 hr weeks and some work 80hr weeks. Some physicians take call, some are in private practice, some work for a hospital, some take insurance, some are cash-only, some see general patients, and some do procedures only.
Just to give some examples of the complexity of physician salaries: I know a psychiatrist making $600,000+/year. I know another psychiatrist making $110,000/year. I know a pediatrician making $100,000/year and another making $350,000/year. I've seen a dermatologist making $180,000/year and another $1.1 million. I know a family practitioner making $90,000/year and another making $750,000+/year. I know a general surgeon making $180,000/year and another making $900,000. I've seen a psychiatrist moonlight in residency and make more money than practicing physicians with 10 years experience. Salaries literally vary $200,000+ in every field, and these are NOT outliers. Many people are on both sides of the spectrum.
With all this variety, medical students still take average salaries into account when choosing a medical specialty. I guess this makes sense if you want to work for a group practice where you have little say in management, take minimal call if any, and work the "average" hours/week in that field. If you actually have any business sense, don't mind working more than average, or can stand call every once in awhile, "averages" aren't very useful.
I guess my advise is this: If you want to practice "average" medicine and come straight home to your family, pay attention to average salaries because you will end up with one. Maybe it is worth doing anesthesia over family practice if money is that important. It just depends on your priorities. However if you really enjoy a specialty and want to make a good amount of money at the same time, you can do it in ANY field. Sometimes it takes more work and definitely more risk, but every field can be extremely profitable if you work at it.