I currently work with ASP.NET MVC and I'm going to switch my professional development efforts to it in the coming months. I had contact with many languages and web frameworks over the past decade. C# is a very mature and powerful language, and the asp.net mvc framework just seems to click with me. I will continue to use jquery as my main javascript library. I will also continue to play with python / django and other solutions in my spare time.
I just like c# so that's probably the reason why I chose asp.net mvc over other solutions.
Seems like MS finally came up with something decent (considering the asp.net web forms mess... quite a feat)