On a larger screen (50″+), most people will be able to notice the difference between a 720p and 1080p set…with some caveats.
First, you must be comparing a true 720p and 1080p set. Simply running a 720p signal to a 1080p set won’t work for this purpose because the 1080p set will upconvert all incoming signals to 1080p. Second, the only source for true 1080p video right now is blu-ray. Most TV stations that are in HD are only using 720p with only a few using 1080i.

Tags: 1080, Average, Between, Difference, HDTV, Notice, Person