I am hoping to make my GUI html based, using the Tornado Python library to serve 2 pages on the network; the actual GUI on one port and an admin-type page on another.

GUI

Serving the GUI will allow my son to access and use his Media player via his tablet when elsewhere in the house; not entirely necessary for videos but greatly useful if/when I expand the unit to run pygame games.

Admin Page

This second page will only be accessible by myself over the network to define settings for things such as timers, any automation settings etc

Using Tornado will also allow me to set up web sockets, which will be my primary method of passing command between the two Pi's - more on that in the 'Dual Pi Setup' Blog.