I'd really question the claim on C#/.Net being the best Web programming language. Yes, you can eek out a performance benefit over Python, but many people prefer Python and its frameworks over C#. It's also proven to be a viable road for startups.

IDEs for Python have improved a lot, and the more passionate Pythonists might fault C# for actually needing IDE tooling for being bearable...

I can see why you would prefer C# over PHP, C++ and Java for Web programming though.