What is the highest paying programming language?
Like a lawyer answering a typical question on a particular case, I would say, "it really depends" ;-)
First, if you follow your passion and really get into programming, it doesn't really matter what the programming language you use, you will excel and be rewarded for that. People making big bucks, with java, c/c++, python, ruby on rail, scala, you name it.
Second, there is a concern about the market size for certain programming languages. For example, java, c/c++, python, ruby and php are some of the hottest languages in the current market. So, there are more jobs with these languages. But, again, there are more people who are skilled in them too.
So, it is all about finding your passion and a niche. If you are passionate about, say, Lisp, you can still find companies that are looking for programmers to build expert systems, with a pay range of $90,000 to over $100,000 per year.
All that said, I would take a balanced approach when considering what the programming language to learn next. The way to do this is to use the 80-20 rule. for example, I would put 80% of my consideration on the passion, if I am passionate about this new language or not; then I would put 20% of my consideration on whether it is currently hot on the market or not. The resulting language is the one I would pick.
Wouldn't you agree?