Viewing Red's 4k showreel being projected off their Redray system. Very impressive! 

This level of resolution in what could be a home viewing experience leaves me convinced that 4K display will be a very likely and seductive home viewing experience. Particularly the natural history sections were mesmerising in their level of detail. 

And some solid statistics from Sony as to why and when 4K is needed here:

http://pro.sony.com/bbsccms/static/files/mkt/digitalcinema/Why_4K_WP_Final.pdf