I recently had to advise a college on proper display size for a large art studio. The following two articles from ProjectorCentral.com came in handy.
What is aspect ratio, you ask? Aspect ratio is the ratio of the width of the screen to the height of the screen. Essentially, it describes the shape of the rectangle. Today the most popular aspect ratio for consumer video display is 16:9, which is the standard HDTV format. The numbers mean that the picture is 16 units wide for every 9 units in height.