Choice of Language for Large-Scale Web Apps?

anyon wonders: "PHP is the most popular language for the web. eBay uses ISAPI (C), Google uses C/C++ (search), Java (gmail), and Python. Microsoft uses ASP (what else?). For small web site, it really doesn't matter. What's your take on language choice for large-scale web applications? Maybe language choice is irrelevant, only good people (developers) matter? If you can get the same good quality people, then what language you would chose? Considering the following factors: performance, scalability, extendibility, cost of development (man-month), availability of libraries, cost of libraries, development tools? Has there been a comprehensive comparison done?"