>If you were going to develop a new "responsive" web-site to handle mobile and browsers, what combination of packages would you use to do so? I'm coming from Silverlight, wpf, wcf, entity framework, etc.

I've been very happy with the combination of MVC, heavily customized Bootstrap, FontAwesome and AngularJs. Angular in particular will probably be a good find for the two-way databinding features you're used to from WPF.

It's been pretty amazing what we've been able to build with this combination, in terms of how responsive and flexible the UI is especially compared with what was possible just a few years ago.

One thing I would mention that although I use Bootstrap, I would recommend working with a designer to get a really optimized UI. If that's an option in the budget that's very much worth it to make sure you get your UI looking nice and smooth. Bootstrap is great if you as a developer have to deal with the UI, but you definitely will want to tweak it a bit for the application to not look too generic. I found 'tweaking' not super easy though - there's a lot of stuff that needs to be modified.

+++ Rick ---