Comment tomato tomato (Score 1) 801
I work for a large-scale ISP/Media/Publishing company and we just went through about 12 months trying to analyze this question. In the end, we resolved that no language stands out of the pack once you put them in a scale, heterogeneous, production environment, that connects to a wide variety of backend services.
If your developer pool knows one language over another, you're likely better off just going with that lang. If you're C#'ing it, you're stuck w/ MSFT VMs and servers. If you're Java'ing it, you have to wade into all the different VM/app-server providers, though we concluded they're all the same over a six-month period; the engines themselves are commodities at this point.