If I was to write something like this right now. I would probably use the MEAN stake.
MongoDB
Express
Angular
Node.js
With NodeJS and express you can have it do your api then add AngulerJS and Web Sockets to those two and you will have a very resonsive Web based UI.
Here is were it gets interesting. Python, C++, or C#. Python works with Nodejs very well. Windows 10 under the hood has some big changes which will make it very interesting for development. The new Windows Universal is really new (it is not even released) and very interesting. I have seen it called Core and Windows IoT. I'm right now toying around with Windows IoT on a Raspberry PI and attempting to create a MySensors gateway. I have had some adventures, and am close to putting it away for now until the next build, but it could be very Interesting.
I would set it up to use the Vera http API first and then add support for Z-Wave, MySensors, then Insteon.
