G'day aariel1003,
EDIT: Apparently I can't post links as my post count is < 10.
Try going to
h t t p : / / content . mycareer . com . au /salary-centre/engineering/ and
h t t p : / / content . mycareer . com . au /salary-centre/healthcare/. Hopefully that works.
While I'm not trying to suggest that MyCareer is indicative of the job market at large or employment trends in Australia, it does give a reasonable idea of current demand for particular industries. As you can see, most Engineering professions have an average salary of $75,000 - $95,000 (note: these are not averages for graduate salaries, but for the whole industry) compared to an average of $120,000 for medical practitioners.
If you have been keeping up to date with employment news (I recommend reading the BusinessDay section of The Age if you live in Melbourne), you'll note that especially in Electrical engineering there is an ageing workforce and they won't be around for ever. Expect demand (and hence pay packets) for electrical engineers to skyrocket over the next ten years.
With that said, you shouldn't base your career decisions on potential dollars. Both these particular fields have extraordinarily high attrition rates and unfortunately, education doesn't come cheap. A four year Engineering degree will leave you with a minimum HECS debt of $28,000 (low-end guess) and a six year MBBS will leave you with a debt much closer to $50,000+.
Also take into account that even after your MBBS, you're still looking at another four to five years as an intern at a hospital working exceptional hours for decidedly little pay.
What I'm trying to get at is that you'll only succeed in one of these fields if you have an absolute passion for them. Of course, if you're passionate about anything, you'll excel in it and thus will find someone to compensate you for your efforts.
I hope I've been of assistance and you do see this reply sometime.
