720p 1080i 1080p 720 horizontal lines. 1080 horizontal lines. 1080 horizontal lines. Progressive scan. Interlaced scan. Progressive scan.

In general, the higher the resolution of a TV, the sharper the picture, and the higher the price tag.

720p has an image resolution of 1280 pixels by 720 lines. It was the first available HDTV resolution but is no longer as common since prices have come down on 1080 models. By comparison, a 720p TV has twice the resolution of an analog TV picture.

1080i has a resolution of 1920 pixels by 1080 horizontal lines. However, it is interlaced, so the lines are painted on the screen in two passes of 540 lines each. The picture quality is fine for slow-moving content but not as desirable for fast-moving objects. 1080i was once the standard in HDTVs, but no more. Its quality is not much better than 720p TVs.

1080p has a resolution of 1920 by 1080 pixels, and it is a progressive scan display rather than interlaced. That means each row is scanned in sequential rather than an alternate order, providing a picture with a full 2.07 million pixels. This is currently the best-selling TV format, and it provides the best picture of the three models mentioned here.

Price: You Get What You Pay For