That's some good information, but definitely lacks the meat of how this applies to 1080p vs. 720p (768p?) in the video world. I would also have simply avoided the explanation of arcminutes and simply said "1/12th of one degree is 20/20 visual acquity and about 1/30th of 1 degree is the limitation of discerning objects" Then tied it altogether with what the heck it actually matters to any of us.
The S&V chart is a great example of mapping out why 1080p matters - and more importantly, when it does not. Most people tend to say that 1080p matters only above 50". That simply isn't the case, resolution is all about the screen size, versus your viewing distance, versus your actual ability to see. A person with 20/20 vision sitting about 1.5x the screen WIDTH (not diagonal) is going to visibly see the pixel structure of whatever display they are viewing if it is 720p. But, this puts someone about 6 feet from a 50" display... which most people would find annyingly close for day to day viewing anyway!
It has always seemed to me that 1080p was overblown for most viewers. It's great marketing, but reality maintains that most people think that a 42" plasma, viewed at 10 feet, is HUGE!
It isn't, in fact, it tends to be a bit small. Yet, many people don't feel that way. But, they do think that 1080p matters. How silly.
The other determining factor, which is incredibly critical to all of this, but is rarely discussed... The source material.
It isn't enough to have a 1080p display. You have to feed it 1080p! Since most people include things like DVD (480i) and SDTV (480i) and HDTV (720p/1080i) in their typical viewing habits, it is only a few select sources that can even deliver true 1080p content. What matters though is that a person who watches a lot of regular TV needs to make their screen size smaller for that content. Resolution doesn't even matter that much!
Instead, the important factors remain contrast and color accuracy, because those are far more noticable than resoluiton. I would add that a display with a good processor inside will also show a much better looking image than those with cheap processors. Vizio, is one that I would consider to have 'weak' processing, while Panasonic tends to be better. You may have lower resolution (or the same) with Panasonic, but the better processing combined with similar contrast will deliver a better image from the Panasonic to most viewers. Only when the source jumps up in quality, and you are actually sitting close enough, does higher resolution matter.
ie: I have a 854x480 42" plasma in my master bedroom. This is the bedroom where our heads sit about 13 feet from the screen. Upping the resolution to HD levels (1024x768) or to 1080p? Wouldn't make a damn bit of difference to my viewing quality.