Integrated house on a budget

Are you going to do this yourself or hire someone?

I think part of it is people are confused by your goals as stated in the original post.

Most serious home automation is done via "systems" from companies like Crestron, Niles, Savant, Lutron, Control4, etc. Attempting to "go your own way" tends to get problematic. I speak from personal experience as I've spent quite a bit of time trying to do so myself. It comes down to a few specific things.

1.) Complexity of Software

Lets face it. Most of what you're buying with a home automation system is software. Very complex software. It needs to know what devices it's controlling, what device is controlling it, what media to stream, what state each device is in (on, off, standby, etc). It gets complicated quickly. There is no open source or user installable software that I know of that can do this which makes a large part of what you're wanting to do impossible.

2.) Hardware

You're wanting to build most of your equipment yourself from the sounds of it. That opens you up to several topics such as HTPC construction, etc. I'm sure most people don't even know where to begin on that one. Most of the systems that do this type of thing use dedicated, closed systems due to various DRM issues.

I'd recommend narrowing your system design requirements down to some specific goals and present us with them.