Highest paying job in what field specifically?
In the medical field, the highest earners are arguably the surgeons.
General practitioners, orthodontists and pediatricians are high earners in this field as well.
Pharmacists also get decent salaries.
If you're good in Maths, the best work for you is to be a statistician or a physician.
These guys get paid really high.
Other options include computer-related courses like computer science or IT.
If you're good in accounting, I mean REALLY good, the best course to take is business management or any other business-related course.
The money you earn in these jobs leave the other professions in the dust, especially if you own your own business firm (you should manage it well, of course).
Then again, if you've got the talent and/or the looks, you can always go the easy route and make big $$$ by becoming an athlete, a model or an actor.