Ask: Transition from Microsoft stack to...?

It's going to be hard to say much without starting some biased flame war, since in the end there's nothing that one framework can do that another can't, really.

All of the languages mentioned above have pretty good ecosystems around them. I think Ruby's is the strongest at the moment, but if you're more of a python guy no harm in that :P.

Honestly I learn as much as I can, and as such have done at least a little bit of dev work in all of the above languages plus some :P. Never hurts, and you'll be able to make a much more informed decision yourself afterwards.

Clojure or Node.js. Since both are first-class on Windows, you can continue using the tools you are used to.

I also write on the Microsoft stack full time at work.

About a year ago I started working with Ruby on Rails for all my side work and hobby projects. It really is an awesome mind shift from .NET.

So I guess my vote would be take a look at Ruby on Rails!

I do rails and aps.net apps. Check out rails and also consider doing current .net apps OSS/rails style. See http://www.servicestack.net