Christoph: i cannot speak for canada, so this is all from what i've seen and am experiencing in the uk now.
Ok, becoming a doctor here, has HUGE fanancail pay off in comparison to other routes. The big problem is University. Not everyone who wants to do medicine can afford to do so, over here you only pay upto £1200 a year on tuition fees a year. If your parents earn under a certain amount, you dont pay any tution fees. So what does that mean?
Well, my freinds are all doing 4 year courses, at it's costing them around £5000 a year. Which they're paying with student loans (Student loans: loans for student's, which are 0% intrest, and are payed when the person begins to earn more than £10,000 per anum). Now it's doesn't take a genuis to tell you, even with working in summer and a little through out the year, there's gonna be a big bill to pay at the end. That one fo the big factors that puts poeple off.
Also, the idea of studying for 6 years, with none of the fun stuff other courses offer during the course year. THe fact that your friends will have been working and already begun to climb the ladder, while your still neck deep in books isnt really the most inticing aspect of the course.
I think medicine is becoming less popular here, simply because alternate career paths are looking better and better.
Job prostpecs are looking better than ever though. The last year in your course, you'r actually paid £18,000 (jnr House officer , I think that's the correct title). And the ladder is very long and very HIGH. You can earn £60,000 a year woking as a consulant on the NHS alone, and then you can add upto £120,000 from privait clincs etc etc.
Also there is the oppertunity to work in the states, where thanks to good old capitlism, the rich get even richer, and consultans can earn HALF A MILLION a year!!!!! You may see why i would like to go work in the states :D, lol. Oh yeah and research oppertunities are great here, and excellent across the pond.