The beginning of the HD conversation is choosing the magic looking glass that will become the centerpiece of your new home cinema. My personal means of making recommendations in this department is in dispelling myths and focusing on the regular human budget.
If you are comfortable dropping $6k on a Pioneer Kuro plasma, you either know this stuff already or have an assistant to do these things for you and you don't need me. I think the majority of folks out there are looking for something affordable, but not cheap. I don't care about gaming, so the following focuses entirely on watching movies and TV shows.
The Buying Commandments
Here they are as handed down to me by The HD Godz (cousins of Jeff's Movie Godz):
1. Thou shalt not buy a store display model.
2. Likewise shalt thou not buy an open-box, returned, or "as-is" model.
3. Thou shalt never even consider an HDTV marked 720p or 1080i.
4. Thou shall do thine research on bundled Blu-ray players you see in ads.
5. Thou shalt not be swayed by bundle offers for inferior products.
6. Thou shall not be swayed by Dynamic Contrast Ratio or other Contrast Ratio specs.
7. Thou shalt require the use of the display TV's remote control to adjust settings.
8. Thou shalt require a store associate allow you to connect a Blu-ray player over HDMI to the TV you are considering.
9. Thou shall not be suckered into multiple TV deals (2 smaller for the price of one).
10. Thou shall invest the time and patience needed to make a good decision.
Which to Choose?
The Brand
I personally went with a 47" LG Class LCD. The first major myth to shred (with some qualification) is about brand equating quality. The nuts and bolts and transistors in the majority of HDTVs on the market feature the same LCD panels made by the same physical manufacturers. The primary difference is in the name plastered on it and the menu layout.
You don't have to pay for the Sony label or fight with your friends about the relative superiority of Sharp, Samsung, or Panasonic. I would, however, stay away from store-specific brands like Insignia (Best Buy) and other budget folks like Westinghouse, Polaroid, and Vizio. Vizio is really eager to position themselves as "just as good" as the top brands, but they aren't based on customer service and warranty support horror stories. In the interest of full disclosure, my wife works for Samsung in a department wholly unrelated to their TV division.
480/720/1080 and Screen Size
The bigger one is not necessarily the best one.
The top resolution on HDTVs is 1080p, which in basic terms means the display is 1080 pixels tall. Think of pixels as little squares stacked on top of one another. You can have a 1080p monitor that measures 30, 37, 40, or 65 inches. It doesn't matter because pixels are a relative form of measurement. A "pixel" is not exactly a certain number of centimenters, millimeters, or inches in size.
The bigger the monitor, the bigger your pixels. It's for this reason that going with the biggest display you can afford isn't necessarily a good idea. Of course, the smaller you go, the less enjoyable it is. To get what I'd consider reasonable enjoyment out of Blu-ray and true HD content, I wouldn't go smaller than 37" or larger than about 51". Make sure you measure your viewing space before leaving the house and try to get the same distance away from the TV you're looking at in the store. Bigger than the 47" we have would be too big for how far away we can get from the thing.
LCD versus LED versus Plasma
LCDs are the most affordable monitors out there. Samsung's new LED line still uses LCD panels, but different backlighting. TVs referred to as "LCDs" are backlit by compact fluorescent bulbs. This is what most of the world and I can afford. The other two types are what you ask someone to "help you invest in" or think really hard before budgeting.
The new "LED" models feature cleaner, cooler, brighter LED backlighting that uses less power and produces better overall picture quality and contrast. They cost more, but they really are gorgeous. Plasmas are the best overall when it comes to contrast and picture quality, but the price tag shoots up even more so than LEDs.
Plasmas are not prone to burn-in the same way front projection sets were (and are) [edit: I corrected some erroneous info thanks to a tip from pal Luke Mullen]. These are the best of the best for contrast and color depth, and with that comes a higher price tag. The LED monitors are projected to eventually outdo the Plasmas in quality. And no, just because it's a Plasma doesn't make it okay to get one that's 720p (see Commandment 3).
User Reviews Are Generally Worthless
Most people out there who've bought an HDTV don't have any idea what they're talking about when it comes to what you want it for. Additionally, there's no way to know who any of these people are. Seek out enthusiast hotspots like the Home Theater Forum and reviewers with a solid track record. If they talk about contrast ratios and other meaningless crap that isn't actually quantifiable, ignore them. If they talk about relative contrast (better than most, not impressive, etc.) that's qualitative, then pay attention.
The In-Store Demo
Demo Over HDMI
Plan to spend a solid afternoon playing around with TVs at a store. This isn't something you want to just roll the dice on. I've yet to find a store that has their demo sets plugged in over HDMI, which is how you'll connect your HD cable box (if you have one), Blu-ray player, and game systems. You aren't getting a real look at what the TV can do unless you've got a Blu-ray player connected over HDMI.
Some stores like Best Buy have little showcase rooms that have demo players set up with correct cabling, but they're usually plugged into the super-expensive sets someone's sales manager would love for them to talk you into buying. Depending on the store you're going to, you may have to bring your own player and cable. If the store wants your business, they'll work something out.
Buying a few Blu-rays that are well-reviewed and having them in-hand isn't a bad idea. Buy them from the store you're at (likely Best Buy based on limited options) if you want to show them you mean business. Pick some from different eras, like the 30's/40's, the 60's/70's, and an 80's-present one or two. You want to see how it handles different content.
Presets for Different Content
Don't expect 70-year-old movies to look great on the same settings as Public Enemies or Easy Rider. You want a TV that allows you to easily set a few presets and quickly swap between them if you plan on watching a wide variety of content. The Third Man will not look good with the high sharpness needed for watching Zodiac or another HD-shot feature.
Contrast Ratio
This specification honestly means nothing and is more a marketing tool than a technical specification. Your two human eyes are a better calibration tool for your perception of contrast than an arbitrary proportion that every manufacturer measures differently. You're looking for the darkest black and the depth in shades of grey you see. Turn down the Backlight and fiddle with the Contrast and Brightness settings. Mess with the Sharpness while you're at it.
Don't Buy Right Away
You should be tired after your "field trip" so go get something to eat, go home, and sleep on it. It's not going anywhere.
One last thing...Don't Get Gouged on Cables
HDMI cables are how you connect HD devices to one another. They should be cheap, or you're buying in the wrong place. They don't need to be platinum or premium gold-plated of some other bullshit like that. Time Warner Cable gave a couple 6-foot ones to me for $10 apiece, but you can get them for even less if you plan in advance. Monoprice.com has some for $8 (less for more). Check with your cable/satellite provider too, they'll be happy to sell you extra ones.
The HD Guide is an ongoing series focusing on the evolving world of HD in the home: getting started, understanding the lingo, and appreciating the best (and worst) discs that are out there.
On the schedule for tomorrow is a set of three installments: What's So Great About Bluray?, Choosing a Blu-ray Player, and TV in HD. Depending on how the day goes, I may squeeze in It's Not Blu-ray, It's HBO, but no promises.