..is to look at your passion and talent. Of course, you can't ignore the job market, but it should be a secondary consideration
For example..when programming is the HOT market..
The talented, passionate people do very well because of their talent and passion..and are rewarded handsomely (like me)
The not-so-talented or passionate may get a job during the boom, it may even pay well, but when the bust comes, they are the first ones "staff reduced"
NEVER pick a career based on the job market unless you have (at least a little) talent and passion for it