Top 5 Must Owns?

Hello!

I'm new to 4K and have just started with a few movies. What would you consider the top 5 4K purchases that best show off the medium? I'd like to make sure I have top quality stuff.

Thanks! 😀

Edit: Thanks for all the suggestions! I have a few more to add to my list, it seems. Also, I blame all of you for purchasing a refurbished C3 just a few minutes ago.....

I told myself I wouldn't buy a new TV until next year!