Have been learning HTML, XHTML, and CSS for a number of years now and really feel quite comfortable constructing my own web pages/sites. But now i want to move on as it were and start learning a full blown programming language but which one?

It has been suggested that i learn either Python, PHP, or even C++

Would really welcome any and all advice on this subject.

Many thanks

I would say C++. If you can learn it, you would find learning other languages a piece of cake.