Although this question shouldnt be here...but personally I would say all career paths you are thinking about have good growth prospects. But dont choose a stream because it has good growth. As if you dont like it, it may not be worth the effort in the long run.
Talk to some colleagues or friends who are in specfic streams like enterprise voice,service provider, or core routing etc, see what does the work actually requires, if you have a penchant or liking for any of those fields expore it more and then choose a path, if you like all then plan and achieve each path with a pre planned long term plan.
This will surely ensure you will choose the most rewarding career path in the long run.
All the best.
Thank you for all your responses. Three different views and I will consider all of them right now I got a job as a support engineer going to client sites will gain some experience and will decide on which path to take
You have to do what you feel most comfortable with. What experience do you have? Where would you like to be in 2 to 3 years? I would not gauge the cert on how much money you can earn, instead.. go with what you can do best!