I would recommend having a "back up" technology just in case. Try to go for a quite different language/technology that is more "hype" (objective-c, nodejs , f#

I would recommend having a "back up" technology just in case. Try to go for a quite different language/technology that is more "hype" (objective-c, nodejs , f# , scala, haskell , golang, python, whatever). Nobody knows for sure what the next trend will be , so just cover yourself. You don't need to switch to that new tech full time, but just enough to be able to answer a few quizz question with it in interviews.