It should be a joyous occasion.

You march into your favorite big box electronics mart with an HDTV purchase just moments away.

But then... the decisions. How big? Plasma or LCD? Or maybe projection? Special cables? A new DVD player? Blu-Ray or HD? Professional installation? Home theater gear for audio? Antenna?

Lots of questions, and we haven't even mentioned price or brand. And we won't. Those are your personal decisions.

HDTV Shopping 101

This is not a "what is" article about HDTV, And we won't get into the federal policy details that will convert the nation to DTV (digital TV in 2009). The good news is that any HDTV set you buy from now on will be fully compliant and have a digital tuner built right into the set. (That wasn't always the case). This article is for anybody who has decided to buy an HDTV set and needs a little help with some decisions.

The big question is "How big?"

This probably is your first decision because size will impact many other factors. Price range, installation, resolution... heck, even the furniture you need to hold the thing up.

HDTV sets are available from as small as 15 inches to a whopping more than 70 inches. This measure is diagonal, corner to corner. The modern HDTV screen is less tall and more stretched out than older TVs, so you will probably want a larger screen measure than you have now. A 27" HDTV screen would feel much smaller than an older 27" TV. To maintain the feel of the size in this case, you would probably want to go to a 37" HDTV set. People would be about the same size on both examples.

Here are several more size considerations:

If your average viewing distance is 7' or less, look at sets 37" or less.

If your distance is 9' or more, sets 42" and up should do the trick. In between, 7' to 9', 37" to 40" should work.

If you can't justify the price tags on the larger sets, take a look at rear projection HDTV sets. They cost less than large LCD or plasma sets, and can perform very well.

Hint: Since the aspect ratio (shape of the screens) is so new to most of us, it may be useful to visit a store with a tape measure, find the size you think is right, go home and cut out a screen shape from cardboard of what you think is your preference. Place it in the room. Nerdy stuff but you want to get this right. This will also help you make decisions about any furniture investments you might need to make.

Most people, as they investigate HDTV for the first time, buy bigger than they had first planned. You'll find the beautiful pictures will stay sharp and crisp even as screen size increases.

LCD or Plasma?

These are the two leading technology types of HDTV screens. They have a lot in common, but there are differences as well.

They both can make great pictures. They both can be used to make the amazingly thin sets that dominate the market; so thin both can be wall-mounted. Traditionally, some LCD sets had restricted viewing angles, but with recent improvements, both plasma and LCD sets provide wide viewing angles. And they both come in a wide range of sizes.

Here are a few widely held observations to consider that may not be true of every brand in every size:

LCD sets are brighter and more suitable for viewing in rooms that may, at times, have bright ambient light. Plasma sets perform best in dimly lit rooms.

LCD units are about 1/2 the weight of plasma units. This may be significant for do-it-yourself installation, especially wall mounting.

Some experts think plasma gives a smoother, movie-like quality. But, compare for yourself, you may not see a difference.

Over time, an LCD set that starts to fade can be rejuvenated with a new set of lamps. When plasma sets begin to fade, there is nothing to reverse the process.

Lots of people believe LCD units provide the best pictures under 42" while plasmas dominate the 42"+ market (and they can be a whole lot cheaper).

Recent improvements in both types have minimized the differences. Either LCD or plasma technology can give you a great HDTV experience.

What about projection units?

Big, fat projection units took a back seat when ultra-slim plasma and LCD sets became affordable. But now, rear projection sets are slimmer than ever and offer the best price-per-inch value in the market. There have been quality improvements as well but viewing angles may be slightly restricted.

Front projector, ceiling mounted units give the biggest picture of all, up to nine feet, projected on a screen. And the quality of the image will amaze you. True home theater. For most people they may require professional installation.

DLP

Digital Light Processing units are one type of projection unit worth a closer look. They handle a wide variety of lighting situations and often equal or surpass LCD and plasma sets for picture quality. Because DLP units are projection sets, they are not available as thin, flat screen panels. On the other hand, they can be a real bargain and tend to be lowest cost-per-inch of all.

720, 1080i and 1080p

Everything you look at will have one of these numbers. They refer to the number of scan lines measured from top to bottom of the screen. The more the merrier but 720 may be enough for sets 37" and below. You definitely want 1080 for the larger sets. Don't settle for some "line doubler" system or "video turbo-charger". You want the real thing.

The "i" in 1080i stands for interlaced, sort of like all the charged particles cascading down the screen. The "p" in 1080p stands for "progressive' with the information spreading across your screen like a floor mop, back-and-forth and down. Conventional Wisdom credits "p" with a "movie-like" look. But Conventional Wisdom isn't paying for your set. Look and compare. Frankly, we don't see much of a difference.

Getting the HDTV signal

One pleasant surprise for many people is that locally broadcast HDTV, like KARE 11-HD, can be received over-the-air for free with an old fashioned VHF/UHF antenna. We like to just open up an antenna in the attic and aim it at Shoreview, Minnesota. Cable and satellite services are increasingly available in digital formats as well. A broadcaster must be sending out an HDTV signal for you to receive HDTV. Your set does not convert a digital or analog signal to HDTV.

At the store

Fifty perfect pictures side-by-side. What next? You can start doing your own comparisons. Some things to look for? There are slight variations in color on the warm-to-cool spectrum. There is no right choice here--it's your preference. Look carefully at action sequences. Look for any weakness around the edges of quickly moving objects--either slightly jagged or soft ghosting. Check the viewing angles, especially if the projection sets interest you. In most stores, the sets are probably being fed by a HDTV signal from a satellite. See if a salesperson can switch to over-the-air for you. Try to ignore brand names and prices--shop with your eyes then check to see if your pocketbook agrees.

Only the beginning

Once you've picked out your dream machine, you have several decisions (and expenses) ahead of you.

Audio. HDTV is more than just a visual leap. It offers a thrilling, movie theater-like audio experience. Your set will have small speakers that produce swell audio, but to realize HD's full audio potential, you'll want to look at a home theater or a surround sound system. Speakers all around the room put you inside the action. Another expense but totally worth it.

Installation. A lot of people turn to professional installation. Just getting the set home and out of the box can be a challenge. If you decide to do it yourself, give yourself plenty of time, plenty of room and helpers. Make any furniture or wall bracket purchases before hand. If you want the pros, your retailer will be happy to arrange it.

DVD players. Your old one will look very good on your new set, but not as good as the new high definition formats. Two formats, Blu-Ray and HD-DVD, are duking it out right now. They may coexist for years, or one may kick the other off the planet tomorrow. Either will give you spectacular results.

Inputs and Outputs. Check with your salesperson to make sure the set you choose has ports for plugging in everything you want. Some common needs are DVD, computer, video camera, and home theater audio systems. But you may have a DVR or video game system, as well. Some people may even want to keep using their VHS players.

Cables. Special cables may be recommended to hook up your system. Some can be quite expensive. This can become quite costly and eventually becomes a question of how many degrees of perfection you are willing to pay for. Most often, the lower priced cables work very well for short distances (six feet or under). Higher-priced cables may be needed for longer runs.

It's a wonderful time to buy a HDTV set. Prices are down and quality is up. Many of the problems you have heard about in the past, like limited viewing angles or expensive separate tuners, have been solved. More programming is broadcast in HD every day; you can even see local news in HD from KARE 11.

Enjoy your new purchase.