I bought my first 4K TV last month and am really enjoying it. I've watched several classic and recent movies in the higher format recently and gained some new visual perspective on some of them. I have 2001: A Space Odyssey, Blade Runner among others in the UHD Blu-ray format. Those were the first discs I watched and recommend them highly as reference discs if you've updated.

Thought I'd start this thread to consolidate all the talk of 4K and even beyond, since the upcoming (maybe?) Tokyo Olympics were set to be the first filmed in 8K, and 2001 has already premiered in that format in Japan.