2160p doesn't quite roll of the tongue as 1080p.
4K (UHDTV / UHD / Ultra HDTV) sounds better.
If you want 4320p / 8K / Super Hi-vision you have to wait 4 more years for these to come on the market
http://www.techradar.com/news/television/hdtv/sharp-dazzles-with-8k-tv-prototype-vp-says-production-about-4-years-off-1124330
You should wait anyway until HDMI 2.0 is suppored, otherwise you're stuck with 4K in max 30 fps.
8K broadcasts to start in Japan in 2016
http://sploid.gizmodo.com/8k-tv-films-arrive-to-japan-and-they-feel-like-looking-1464050347
Meanwhile still waiting for proper 1080p broadcasts over here, instead of low bitrate 720p/1080i mpeg 2.







