General and Practical Rules Of Screen Size
The original rules of thumb on screen size were concocted during the era of CRTs and scan lines and have been massaged somewhat since, and will be massaged further in this era of 1080p.

The older rules for how far back one should sit from a given size screen were essentially written to mask the presence of those unsightly scan lines and the poor quality of our lower resolution sources. Now high-def is here, and superior video processing makes even our legacy video look better than ever.

While all this has changed a lot, one thing hasn't. Most of you will buy as big a TV as you can physically fit in the vicinity of where it's going to live, and damn the rest. And more power to you! Most of the time this will work out fine, just check here and make sure you're in the ballpark with our recommended viewing range for your screen size so you're not overpowering your room or your eyeballs.

Today, with HD becoming a more regular viewing meal, DVD being far superior to most of our legacy video, and the improvements in video processing, the new rule of thumb is:

One and a half to two times screen diagonal measurement is our recommendation for optimum seating distance from the screen.

Keep in mind that some of the cheapie sets sacrifice the processing quality that makes the legacy sources shine. Always check at the store before you buy—look at a screen in your size range and walk off the right distance in the store and make sure it looks good with at least a decent DVD or two.

Below is a chart with a number of common screen sizes measured in diagonal, followed by the recommended range of viewing distance.

40" diagonal screen: 59"- 78"
42" diagonal screen: 62"- 82"
46" diagonal screen: 68"- 90"
50" diagonal screen: 74"- 98"
55" diagonal screen: 81"- 108"
60" diagonal screen: 88"- 118"
65" diagonal screen: 96"- 127"
70" diagonal screen: 103"- 137"