>Is anyone aware of examples of companies who are actually running .NET Web apps in production?

Look around at the web, anything using an ASPX extension is running on the .NET Framework. The mojority of Microsoft sites's like MSN are using it. I don't think Hotmail is though. I'm interested in seeing if that makes the move.

Otherwise, here's some case studies:
http://msdn.microsoft.com/vstudio/productinfo/casestudies/default.asp