That's how it came? Like already done? A spec house? If that's the case, HOLY SH*T, that's awesome, you are golden to go. CAT-5 to light switches is useless, so ignore that. I'd say throw some Sonos amps on the in-wall speakers, and whatever Sonos gear you want in the rest of the house, and then you're all set with the RG-6 and CAT-5. You can just light up ethernet and RG-6 as needed with a switch and cable splitters/amps from the central wiring closet. I'd avoid doing a matrix'ed HDMI system, much easier, and MUCH cheaper to just do MCE and extenders... Ethernet is ideal for that. In reality, all you need is RG-6 to the FIOS router and to your MCE PC, and then Ethernet wherever you have extenders or PCs. That's the ultimate setup.