Let's calculate. With a typical home 42 inch panel sitting 3 meters away. The screen width is around 1 meter, so you have 2 right triangles with major catheti of 3 and minor catheti of 0,5, ok?So the tangent of the angle of one of the triangles is 0,5/3. We need to know the arctangent of 0,5/3, arctangent (0,166) = 9,46 degrees. We have 2 triangles, 9,46*2= 18.92 degrees. You can do the calculations with the windows calc in scientific mode. With the value on the screen (0,166) press [b]Inv [/b]and then [b]Tan [/b]to do the arctangent.
1920 pixels divided by 18.92 degrees of vision = aprox. 101 pixels/degree.
Sitting at 2 meters from the same screen you get 68 degrees, more than that 20/20...
Well, now DIY.
Simon.
P.D. I am not very good at maths so if there is one or several errors tell me. If somebody is very interested in the design of the living room (size of TV and positon of the sofa) I could make an excel spreadsheet.