Help me build my system

 I have a pretty big living room that is open to my kitchen and breakfast area in a house I am building.  I am tired of walking into audio/visual shops that push their one or two brands they keep on the floor.  Here is what I am looking for in the room:
 
I need a new receiver to run movies/watch tv and of course, listen to music.  I have a record player, so phono is a must.  About $1000 budget.
I need a new tv.  Looking for a 50 inch flat screen.  Less than $2000.
I need in ceiling speakers (I know, not even close to ideal) for the front and rear.  The house is wired for 7.1, but I think I will stick with 5.1.  I am more interested in music than the best movie sound possible.  I can use a center channel that will sit out just below the tv rather than putting that in the ceiling.  I can also put a sub in a cabinet rather than in the ceiling.  I don't want to go too crazy on the in-ceilings, but want a decent sound.
As for the rest of the house, I am running a Sonos system that I already own and need a bunch of in-ceiling speakers that will strictly play music off of my NAS through my Sonos system.  These are more for ambient music than serious listening.  But I want a decent speaker throughout the house without killing my wallet.
I am fairly tech/mechanical savvy, so I am thinking of just building the system myself including installing all speakers.  Am I making a huge mistake?
Any help/suggestions would be appreciated.
 
Gregg