If you do a projector, do it right. Don't really need a screen but the paint color is key. Build a frame, LED back lighting too. Cheap and easy. You can get a really good home theater projo for under $1k.
If you get a soundbar don't go cheap. I went w/ a high end Polk and would recommend. I also have surround sound but I hardly ever use it.
More than anything, spend your money on furniture. Deep set couches son.
In and out under $3k. Boom, you got yourself a media room.