It seems as if people argue for the language they picked up first / have most experience in.
I believe the correct answer is not a direct answer, but something along the lines of "it doesn't matter, so long as you learn several, well".
I learned C first, stopped studying C when I tried to make a GUI for win32. ~2 pages of code for an empty window. ~5 lines in Python.
So, the ideal first language is whatever is easy to understand and fast to accomplish something. Instant gratification, in other words.
Should one learn the fundamentals first (assembly/C) or the practical first (python)? The answer will depend from person to person. I personally took the practical first approach.
[1] http://www.johndcook.com/blog/2010/03/03/just-in-case-versus...