Within your constraints, I would vote for Python too. It is an excellent general purpose programming/scripting language with libraries for every imaginable task

Within your constraints, I would vote for Python too. It is an excellent general purpose programming/scripting language with libraries for every imaginable task, object-oriented programming patterns, and some basic functional programming features. The separation of application code from web server is also a nice feature of Python based web applications. PHP is really easy to hit the road running but larger applications get clunkier and clunkier because there is little proper separation.