Career should be chosen on the basis of interest, passion and where your strength lies. When you do something out of passion you would do it at your level best thus making a good investment out of it. The matter of income also does play a major factor when it comes to choosing a career.
try using iseek.org and do a skills assessment. it will tell you what careers you would be best suited for in order of most income and tabs sort it by education level. make a list of what careers you think you enjoy and research what actual employers are hiring for in your area for that career position. I use craigslist to reference realistic income rates. iseek tends too be incorrect on salary