Over the last few years, the price of high-definition televisions has plummeted, but buying one can still be a mind-boggling experience.

Today, there are three basic types of technology for you to consider: plasma, LCD and LED. All of these are thin enough to hang on a wall and produce stunning highly detailed images.

Plasmas utilize small cells containing electronically charged ionized gases, or phosphors, to display the picture. The phosphor is electronically excited to create a glow in the proper color. This produces the highest-contrast levels and the truest blacks.

Plasma televisions are generally rated as having the best picture quality. They have good viewing angles, meaning that they can be viewed from the side better than most other types of displays.

They are best viewed in a dark room. They do not do as well in a brightly lit room, so if you will be putting the television in a sunny room, you will not want to get a plasma. For fast action and sports, plasma holds a slight advantage over LCD, though LCDs have become better in this area.

LCD stands for liquid crystal display. These television displays use the light modulating properties of liquid crystals to emit the light to create the picture. The crystals block or allow light to create different colors.

LCD televisions use a CCFL (cold cathode) backlighting to produce the light to eliminate the crystals. LCD displays have a nonreflective screen and produce very good brightness, which makes them perform better in brightly lit rooms.

Although they can easily be seen from the side, they are best when viewed from the front. Most LCD televisions have a 60 Hz refresh rate. These can have a slight blur in fast-moving action scenes.

Depending on how sensitive your eyes are, you may not even notice this. LCD manufacturers have upped the refresh rate in some of their televisions to 120 Hz. This repaints the screen twice as many times per second and is intended to eliminate the blur in fast-moving images. You will also find LCDs with 240 Hz refresh rates.

Although they are simply referred to as LED televisions, this is a television that uses LEDs (light-emitting diodes) as a backlight rather than the traditional CCFL backlighting. You will pay a premium for an LED television, but they have several advantages over the standard LCDs.

LEDs are thinner, lighter, have better heat dissipation, a brighter display, better contrast levels and lower power consumption than standard LCDs.

If you are interested in power consumption, you will find that plasmas are the most expensive to operate - although all televisions have improved in this area. Plasmas use electricity to light each and every pixel you see on a screen, whether they are white, colored or even black. Plasmas can easily use three times the energy of a standard LCD, while LEDs use as little as half of the power needed to run a standard LCD.

You will find that the size of the screen and the resolution also greatly affect power consumption. The good news is that all of these new technologies consume considerably less electricity than the clunky old CRT (cathode ray tube) technologies of the pre-hi-definition era. More good news is that manufacturers have starting putting energy-rating stickers on their televisions, so you can easily compare the power consumption of the various models.

Another thing to consider when purchasing one of these new technologies is longevity. Most plasma sets have ratings of 60,000 to 100,000 hours to half-life. That means that after that number of hours, the television will be dimmed to about half of the brightness it had when it was new, but it will still be viewable.

Many LCDs are also rated for 60,000 to 100,000 hours, but this is how long it will take before the backlight wears out.

If you keep your television on for seven hours a day, it would take you 23 years of use to get to the 60,000 mark and 39 years to get to the 100,000-hour mark. Keep in mind, however, that there are many other things that can go wrong with these new televisions.

They are highly computerized, and the parts are tightly integrated. The days of pulling the tube out of a television, going down to the corner store to test it and replacing it cheaply are gone forever. When one component of these new flat-screen televisions goes bad, it is likely that the entire guts of the TV will need to be replaced. In most cases, it is more cost effective to replace the television than to get it repaired.

For that reason, a flat-panel television is one device for which you may want to consider purchasing a service policy. My four-year-old hi-definition television has had its innards replaced twice. Each repair would have been about $1,000 had I not purchased a five-year policy. This may not happen to you, but you should be aware that repair bills for these new televisions can be quite hefty.

Now that I've gotten one of the biggest drawbacks of the new televisions out of the way, let me say that our high-def television has given us hours and hours of enjoyment. When I think about the fuzzy gray and white television shows that I watched when I was a kid, the picture quality of these new TVs is nothing less than spectacular.

I'll have more next week about high-definition televisions. Stay tuned.

Contact Sandy Berger at sandy@compukiss.com.