as so many options you might have so many suggestions to such a question could be given ... there is no such thing as the 'best' or 'most valuable' or something like this without taking related things into account. what you should do depends on you knowledge, interests, wishes, abilities ... do you want to go abroad or not, do you want to be more a programmer or an analyst, are you more interested in systems-architecture or in implementing things by your own ... first you should think about what you basicly want to do ... then you could think about what you should do :) ... just a short example: if you think that COBOL is just out or outdated or whatever, and you wouldn't ever think that learning this programming language could be worth the time ... then you should consider that a very huge amount of very important business-processes are currently implemented with COBOL. of course the programmers that are aware of that and have the experience and abilities to maintain that code are quite well paid for their jobs ... but being a young cobol-developer could let you benefit from your knowledge and let you start a quite great career in a company where COBOL is currently used. it might be that such a company is located near you and you would have some advantages besides just knowing COBOL since you might know about things that are related to the business ... or similar advantages. so, as you might see, to give a general recommendation for a specific technology couldn't be serious without knowing more about you and the circumstances that needs to have payed attention to.
one of the other good examples to avoid such 'general' suggestions is the so called 'acyclic behaviour' ... which means for example: it could be said that currently are too less lawyers in a country. a bunch of young students instantly starts their studies and in 3-5 years they are ready. but in the meantime some of the older students finished their studies and got the jobs and now, when the 'cyclic behaving' students are finished they are out of luck since now at this time their might be too less medics or whatever. so you should even think about the future and try to anticipate what could be there ... and then check whether your decision will be good or bad regarding this thoughts.
kind regards
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