Shopping for TVs is, in a word, overwhelming. You go to the store, you start looking at sets, features, shapes and sizes. Suddenly you feel like the only thing you're going to leave the store with is questions and a headache. For example:

What is the difference between HDTV and analog TV?
Do you really need S-video inputs and front RCA jacks?
What on earth is a digital comb filter?
And most of all, does any of this really matter when you're sitting down to watch a movie or a ball game?

If you attack these questions piece by piece, it's really not that complicated. This guide will walk you through the basic decisions involved in TV shopping and explain the available features in plain, easy-to-understand language.

What's Your Type?

The television is one of the most significant inventions of the 20th century. For the whole picture, read How Television Works.

In the past few years, there have been tremendous leaps in TV technology. Twenty years ago, TV shoppers had very few choices. These days, several TV technologies are competing with one another. This makes TV shopping all the more difficult. Each TV type has strengths and limitations based on the technology being used. Deciding what type of TV is right for you starts with understanding the factors that affect a TV's performance.

Viewing range is an important factor, especially when shopping for a big-screen TV. The viewing angle represents the total area in front of the screen that the image can be seen without distortion. When it comes to viewing range, some TVs are better than others. This is based on the technology used to deliver the picture. For instance, because a plasma TV uses tiny lighted cells to produce the picture, if you are viewing these cells at an angle you will lose picture clarity. A traditional tube TV (CRT) uses a cathode ray to paint the screen with the picture. This method allows for a wide viewing angle.

Black level is your TV's ability to produce the color black. TVs create image color by mixing the colors red, green, and blue. Black is the absence of color and serves to provide detail to an image. Achieving a true dark black is something newer TV technologies such as LCD (liquid crystal display) and plasma are struggling to create. To this day, nothing beats an old-fashioned tube TV (CRT) for black level.

Resolution is the number of pixels per square inch. Pixels are tiny, colored dots that combine to form the picture you see on the TV screen. The more pixels there are on the screen, the higher the resolution. The higher the resolution is, the better the picture quality. Resolution measurements are shown in this type of format: 1280x720. These numbers correspond to the number of horizontal and vertical pixels in the image. To give you an idea of the available range, a CRT TV is capable of up to 480 lines of resolution, while an HDTV can produce 1920x1080. You may see resolution abbreviated to only the second (vertical) number, plus a letter "p" (progressive scan) or "i" (interlaced) -- so, 720p or 1080i.

Burn-in is the term for the damage done to a screen by static images that are displayed for a long time. Both tube TVs and plasma TVs are prone to this kind of damage. When a static image like a stock market crawler, station logo or video game score display is left on the screen for a long time, the image gets burned into the screen by the picture-producing mechanism. Burn-ins will appear as "ghost" images on a screen. The chance of burn in can be reduced on any type of TV by setting the contrast levels at their middle settings and making sure static images are not displayed on a TV for hours at a time. A new technology called auto pixel shift also helps plasma screens resist burn-in.

Glare is created when a TV screen picks up ambient light from the room and reflects it back at the viewer. This is a particular problem with tube TVs that have curved glass screens. To counter this, manufacturers provide flat-screen versions that drastically reduce glare. They are more expensive, but may be well worth the extra money if glare is a problem in your home.

Durability is a desirable trait in anything you buy. Once again, the technologies used are the greatest determining factor in the life span of your new TV. LCDs and CRT TVs are known for their long lives. On the other hand, plasma TVs and projection TVs have much shorter life spans despite their much larger price tag.

Price is an obvious factor when shopping for anything. In the world of TV shopping, price is stacked based on the size and type of television. Plasma and LCDs are more expensive than CRT TVs because the technology is newer and more expensive to produce. The most important thing to remember when TV shopping is that the highest price does not necessarily mean you are going to get the best picture.

Screen size is an interesting limitation that affects all types of TV. The limits are set based on the practicality of implementing a particular type of technology for the screen size in question. For example, a CRT tube TV gets taller and wider as the screen size increases. It also gets deeper and heavier in order to accommodate the larger tube needed to produce the picture at that size. CRTs top out at about 40 inches because any larger would make them impractical. LCDs, which are based on transistors and capacitors, suffer from a similar limitation but for a different reason -- increasing size beyond about 37 inches produces a display that is too likely to contain a bad transistor. Plasma TVs and projectors, on the other hand, really have no limit to screen size other than the price.

Each section will present an aspect of the decision-making process and give you a detailed description of the relevant factors. By making decisions along the way, you can whittle away at the choices until you've narrowed it down to one or two sets. Let's get started.

One Size Does Not Fit All

Often, people think bigger is better when it comes to TV screen size; but that is only true to a point. A large TV in a small room will seem awkward and may make watching TV uncomfortable. On the other hand, a TV that is too small will force you to squint to make out details and pull you out of the experience of what you are watching. Making the right decision about the size of your television is the first step in TV buying.

TVs range in size from 5 inches up to 64 inches and greater. TVs are measured by their screen size. This measurement is made diagonally across the viewing area. You can use this measurement to help you decide which size is right for the space you'll be using.

Photo courtesy Panasonic and Matsushita Electric Corporation of America
TV size is measured diagonally across the viewing area.

Start by mentally placing the TV in the room. Unless it's a flat-panel, a TV usually gets deeper and heavier as the screen gets larger. Make considerations for height, width and depth when placing it in the room. Make sure your location is reasonably close to a good power source.

Once you've placed the TV, measure the distance from your couch or viewing area. There is a formula to calculate the optimum screen size based on the viewing distance. Different TV sources alter the equation. The formula is simple:

Source	Calculation
Cable Antenna Video tape	Multiply the number of feet between you and the screen by 4 inches.
DVD Satellite	Multiply the number of feet between you and the screen by 6 inches.
HDTV	Multiply the number of feet between you and the screen by 7 inches.

Of course, very few of us watch only one kind of TV. Use the chart above as a guide to find an average distance and screen size that is appropriate for your needs.

If you already have an entertainment center or armoire that you don't plan to replace, then you will be limited to the TV size it can hold. Remember, when fitting a TV into a piece of furniture, you need to consider depth and weight in addition to height and width. You should also factor in a couple of inches into your measurement to allow for proper ventilation for the new set.

Flat-panel TVs are growing in popularity because you can get a larger screen with a smaller footprint, or even hang the TV on the wall, so space is less of a concern. Ventilation is still important, though, especially for plasmas, which generate a lot of heat.

Photo courtesy Sony
A 32-inch CRT TV is great for a simple home theater or living room set-up.

Generally speaking, 27 inches or less is good for a bedroom or secondary television. Thirty-two inches and larger is a nice size for a family television or entertainment center.

Flat Panel: Plasma

Photo courtesy Sony
Plasma display

Flat panel TVs are all the rage now, with their slim profiles and large screen size. There are two types to choose from: plasma and LCD. Plasma TVs work by illuminating thousands of tiny fluorescent lights to create an image. LCD TVs operate like the screen of your laptop. While these TVs can't be beaten in terms of cool points, there are some things to consider. Here's the skinny...

Plasma TVs
Plasma TVs are not TVs in the traditional sense. They are more like monitors and need an external TV tuner to display broadcast signals.

Plasma displays are digital and have higher resolutions than CRTs. When shopping for plasma TVs, it's important to note that not all plasma displays can produce the full resolution of HDTV. Some Plasma TVs are considered EDTVs (enhanced-definition TVs), with a resolution of 852x480. On the higher end, there are full-blown high-definition plasma TVs capable of a dazzling 1,920x1,080 resolution.

Pros:

They have a large screen size.
They have a slim profile (3 inches thick!).
They can be wall mounted, ceiling mounted, or placed on a stand.

Cons:

They are relatively expensive (though prices have fallen in the past few years).
They are susceptible to burn-in (damage done to a TV screen as a result of the long display of a static image).This can be avoided by limiting the length of time that images stay on the screen, especially for the first few months of using the plasma.
They have a poor black level (ability to render the color black, which affects picture detail).

Flat Panel: LCD

LCDs are larger versions of your laptop computer screen. Just like plasma TVs, LCDs require an external tuner to receive input. LCDs win for slim, coming in at almost an inch thinner than plasma, and they are priced about the same as plasmas of similar screen size.

Photo courtesy Panasonic and Matsushita Electric Corporation of America
A 13-inch LCD TV

Pros:

They have a slim profile (2 inches thick!).
Their retail price is falling (still pricey, though).
Bright and sharp images, especially for video games or connecting your PC to your home theater.

Cons:

They have limited screen size.
They have poor black level.
Images might not look as realistic as on a plasma.

Rear-Projection: CRT

Rear-projection TVs (RPTVs) are great if you are considering a large-screen TV (40 inches and greater). The basic idea of RPTVs is to combine a projector and a screen into one box. The projector casts the image on the rear of the screen. You see the image when you look at the screen head-on.

Photo courtesy Panasonic and Matsushita Electric Corporation of America
RPTV

CRT Rear-projection TVs
CRT rear-projection TVs use three cathode ray tubes to shoot red, green, and blue onto a projection screen. These huge beasts have long been a staple of home theaters.