No reason to go beyond 1080P yet
Scott, as you have pointed out many times, there are way too many factors (HDR, color gamut, gamma, frame rate) to be resolved by the industry before it makes sense to move beyond 1080P. Also, how many of the new displays have really good upscalers to make lesser source material even watchable? I saw a Sharp UHD that did a terrible job of upscaling 720P source material.
My next upgrade will be to a receiver with immersive audio. I have the ceiling speakers and I'm just waiting until the receivers get all 3 (Dolby Atmos, DTS X, Auro) capabilities before buying, so probably end of summer. Hopefully the receivers will have decent pass through of UHD source material for future proofing.
I'll stick with my Sony 1080P projector until all the UHD/4K specs get sorted out. It looks great with Blu-ray discs and does a fine job with lesser sources.