I completely agree.
If you read this article on your computer, laptop, smart phone, or iPad, then you can already tell the difference between 720P and 1080P when viewing a small display --- close up (within 2 feet)! But if you are going to watch movies or TV at a greater distance, then you need a bigger screen; still capable of displaying 1080P, or better.
My career is designing Ultimate Home Theaters, and in that pursuit I utilize the biggest screen dimensions possible. In order to fully immerse your senses, I feature Sony and JVC 4K projectors ( 4,096 x 2,160P & 2,400P ), whose near 10 Megapixel displays can also create ravishing 3D images, with twice again the information going to each eye (nearly 20 Megapixels @ 60P)!
My advice is to always get 1080P displays or better and watch the biggest images, possible. Today, there are worthwhile DLP projectors available for the same price as a flat panel of 50" or so that offer far more compelling picture quality than you will likely see even at the best movie theaters in the world --- save for my own.
Kipnis Studios (KSS)