The 1080p vs 720p, or 720p vs 1080p, resolution decision [(1,920 x 1,080 pixels) vs (1,280 x 720)] should be made with an appreciation that resolution is not the only factor contributing to picture quality. In fact, resolution comes fourth in a recent SMPTE (Society of Motion Pictures and Television Engineers) study which ranked contrast ratio, color saturation, color temperature or greyscale ahead of it in ranking picture aspects the human eye sees in order of importance.

Two factors influence which resolution is more appropriate namely,

Screen size and Viewing distance.

In general terms, the closer you sit to the on-screen image the more detail you can see as the image fills more of your field of vision. So the closer you are getting to the display/screen the higher the resolution should be getting to maintain picture quality. Moving away from the display/screen reduces the discernible difference between resolutions eg. 1080p vs 720p.

Below is a table matching up various screen sizes with the optimum viewing distances for 720p or 1080p resolutions.

A chart of optimal viewing distances in one inch increments is available from HDGuru.

1080p vs 720p Choice for Front Projectors

From the table above it can be seen that the optimum viewing distance for common projected images sizes (100 and 120 inch diagonal) the optimum viewing distance is going to be outside the home theater room. In fact, you even need a large home theater to sit at the optimum viewing distance for 1080p – there is a case for even higher resolutions to be available. So for optimum viewing, you need to purchase a 1080 resolution projector and sit a good distance from the screen.

Keep in mind though that if you choose 720p and are not sitting at the optimum recommended distance then the picture quality is only going to be slightly reduced not vastly reduced. Both 1080p and 720p can deliver excellent picture quality.

1080p vs 720p Choice for HDTV

While you could consider what consider what video sources you might have available (eg. Sony Playstation 3 and Xbox 360 have 1080p games) or the advantage of selecting 1080p to future proof your situation, for determining if 1080p will have any visual advantage over 720p have a look at the following simple chart from Carlton Bale. The chart shows how close you need to sit to be able to detect the benefits of a higher resolution screen. For an answer see where your likely seating distance will fall given your television room layout.

Another factor which will influence a choice between 1080p and 720p for a HDTV is the generally limited range of features in comparison to 1080p models.

Top 5 Bestselling 1080p LCD HDTVs

Samsung LN46A650 46-inch 1080p 120Hz LCD HDTV with RED Touch of Color
Samsung LN52A650 52-Inch 1080p 120Hz LCD HDTV with Red Touch of Color
Samsung LN46A550 46-inch 1080p LCD HDTV
Samsung LN40A550 40-inch 1080p LCD HDTV
Samsung LN32A450 32-Inch 720p LCD HDTV

Top 5 Bestselling 720p LCD HDTVs

Samsung LN32A450 32-inch 720p LCD HDTV
Samsung LN26A450 26-Inch 720p LCD HDTV
Sony Bravia L-Series KDL-32L4000 32-Inch 720p LCD HDTV
Samsung LN37A450 37-Inch 720p LCD HDTV
Samsung LN19A450 19-Inch 720p LCD HDTV Black

Top 5 Bestselling 1080p Plasma HDTVs

Samsung PN50A550 50-Inch 1080p Plasma HDTV
Panasonic Viera TH-42PZ800U 42-Inch 1080p Plasma HDTV
Panasonic Viera TH-46PZ85U 46-Inch 1080p Plasma HDTV
Samsung PN50A650 50-Inch 1080p Plasma HDTV with RED Touch of Color
Samsung PN58A550 58-Inch 1080p Plasma HDTV

Top 4 Bestselling 720p Plasma HDTVs

Samsung PN42A450 42-Inch 720p Plasma HDTV
Panasonic Viera TH-50PX80U 50-Inch 720p Plasma HDTV
Samsung PN50A450 50-Inch 720p Plasma HDTV
Panasonic Viera TH-42PX80U 42-Inch 720p Plasma HDTV

Top 5 Bestselling 1080p DLP RPTVs

Samsung HL67A750 67-Inch 1080p LED Powered DLP HDTV
Samsung HL61A750 61-Inch 1080p LED Powered DLP HDTV
Samsung HL61A650 61-Inch 1080p Slim DLP HDTV
Samsung HL72A650 72-Inch 1080p Slim DLP HDTV
Samsung HL50A650 50-Inch 1080p Slim DLP HDTV

Bestselling Home Theater Projectors

InFocus Work Big IN10 Ultramobile DLP Projector (720p)
ViewSonic PJ513D DLP Projector (720p)
Epson Home Cinema 1080 Home Theater Projector (1080p)
ViewSonic PJ551D 2300 Lumen DLP XGA Projector (720p)
Epson MovieMate70 Portable Home Entertainment Projector with Built In DVD Player (720p)