@starwolf474: I'm an architectural photographer and have photographed a crap load of homes over the course of my career, both inside and out. If I had to estimate, I would say I have photographed over 700 homes during my 16 year career. From my experience, the VAST majority of people sit farther than 10 feet away from their HDTV's. It might be different for people living in apartments, since they don't have as much space, but people actually living in decent sized homes, I would estimate that most sit at least 13-15 feet away for their HDTV's and very few had HDTV's larger than 50".
Then you have the whole quality of eyesight issue and a significant percentage of the population have less than perfect eyesight. 20/30 eyesight is a 33% drop in visual acuity, so those people would have to sit 33% closer or roughly 7 feet or closer (with a 50" HDTV). Those with 20/40 would have to sit 5 feet or closer and so on and so on.
The bottom line is very few people overall can tell the difference between 1080p and 720p on their own HDTV's. 1080p is more or a marketing scheme than anything else and there is no denying the HDTV companies have been very successful at getting people to jump on board. If you have every gone and shopped for an HDTV, you will notice the salesman usually bring you within 6 feet of the HDTV when showing you the picture. This is done on purpose as they know that the closer they bring you, the more likely the person will be able to see differences in picture quality.