In the past few years, television has undergone a revolution. Thanks to high-definition television, we can get unbelievably clear pictures. But choosing an HDTV set can be confusing.

High-definition refers to the resolution of an image. There are a couple of HDTV resolutions: 1,920-by-1,080 pixels (1080i and 1080p) or 1,280-by-720 pixels (720p).

You won't notice much difference between 1080 or 720. These numbers refer to the number of rows of pixels that make up the picture on the TV screen. A pixel, short for picture element, is a single point in a digital image. Standard televisions only display 330 rows of pixels, which is a difference you'll notice when you move up to HDTV.

The "p" means progressive, while "i" means interlaced. With progressive-scan HDTVs designated 720p and 1080p, the picture on-screen is refreshed all at once every 1/30th of a second. With interlaced screens, which is what HDTVs labeled 720i and 1080i as well as regular standard-definition TVs are, the odd-numbered lines of resolution are refreshed first, then the even-numbered lines.

Because they refresh the entire screen in a single pass, progressive-scan HDTVs offer a somewhat cleaner, smoother picture, which can help when viewing sports and other fast action. But overall, both progressive-scan and interlaced TVs are fine.

There are different types of HD sets: projection, plasma, LCD and CRT. Each has disadvantages, but they're all good. Projection TVs are bulkier than plasma and LCD. You can't mount them on a wall.

Projection sets are relatively inexpensive. Digital light processing (DLP) models are the most common type. You'll also encounter LCOS (liquid crystal on silicon), LCD (liquid crystal display) and CRT (cathode ray tube). With DLP, you may notice a rainbow effect. Check the TV carefully before buying.

Plasma and LCD sets are wall-mountable. Both historically have had drawbacks, which have mostly been solved or mitigated.

LCD sets are lighter than plasmas and consume less power. Until recently, they had problems with smearing — motion appeared blurry. Newer sets are less likely to have this problem.

Response time is important. This is the time it takes for the pixels to turn on and off. Aim for an 8ms (milliseconds) or less response time. Smearing is less likely with fast sets.

Smaller LCDs sell for well less than $1,000. Larger models are more expensive than plasma sets.

Some consider LCDs superior to plasmas. But plasmas have beautiful pictures. The smallest plasmas are 37 inches. If you need something smaller, shop for an LCD.

HDTV prices are falling rapidly. If you've shopped for an HDTV in the past, look again. You'll be amazed at today's prices.

Kim Komando hosts the nation's largest talk radio show about computers and the Internet. To get the podcast or find the station nearest you, visit: www.komando.com/listen. To subscribe to Kim's free e-mail newsletters, sign up at: www.komando.com/newsletters. Contact her at gnstech@gns.gannett.com.