I picked my TV size first. I figured out where in my living room I wanted my TV to be, then measured the distance from that spot to where my head would be on the sofa. I then went to the local Best Buy, picked a TV, and then moved closer and further away until I found the spot where the TV filled up the "right amount" of my visual field.
What I discovered at this point is that for me, bigger is not better. I don't like the feeling of being immersed inside the TV. I prefer to see the area around the TV as well. I may be unusual in that regard.
Anyway, once I found that distance between me and the TV in the Best Buy, I measured that distance, and then did a simple proportion test. If I was 7 feet away from a 35" TV and that felt right, and I knew that at home I'd be 9 feet away, then I wanted a TV that was 35" * 9 / 7, whatever that math turns out to be.
Those are just example numbers, but I knew that I wanted something in the 60" range. So then I went looking in the store at the TVs, and I just liked the way the Samsung sample image looked. The only other requirement is that I wanted a TV (with a TV tuner) and not a monitor (without a TV tuner). I also decided against 4K and HDR. 4K because my vision wasn't good enough at that distance to be able to tell (4K TVs only look better close up). Also, for my typical use it would be DVDs and OTA TV signals, both of which a 4K TV has to upscale and interpolate, which is more computer chips to do something I can't see. Didn't make sense. Can't remember why I didn't choose HDR - probably it was a feature mostly available on the 4K TVs.
I think I spent about $500 USD on the Samsung ~60" 1080p at Best Buy, and that was in September 2016.
I'm fairly happy with the TV. It has good picture quality and no issues there. The built in "smart TV" features are kind of primitive and slow, but I am able to hook it up to Amazon Prime and get that to work. Frankly I watch more TV than I want to already, so I kind of don't want a great TV because that would just make my life worse.
