Walking into an electronics store and being faced with a wall of large panel HDTVs can be daunting. Then you're made to feel like an idiot when the sales person starts spewing statistics and acronyms that sound like a combination of Latin and calculus. Buying a flat screen HDTV is far easier than store sales staffs for electronics "experts" make it. You need only consider four questions, all of which can be answered before you step foot into a store.

LCD vs Plasma

There are two basic types of flat-panel TVs currently on the market: Plasmas and LCDs. Generally speaking, LCD HDTVs reflect ambient light better than plasma and, therefore, are more appropriate for bright rooms. However, plasmas generally perform far better in darker rooms, so if you can control the light in the room, you want a plasma.

LCDs are sometimes advertised with technology that can create extra frames between each "actual" frame of footage, sometimes called 120 Hz or, now, 240 Hz. This technology compensates for an inherent problem with LCD technology. Each pixel in an LCD is powered and lit separately, which takes time, measured in milliseconds (8 ms pixel response is too high; the average is around 4 ms.) Each time your picture moves, a new array of LCD pixels have to flicker on and off, which causes the picture to lag or "judder." LCD HDTV manufacturers compensate by creating technologies, such as 120 Hz which doubles the TV's frame rate, to compensate what this pixel lag. Without these compensating technologies, you get what's called "motion blur," faint image ghosts that follow fast-moving objects such as baseballs, jet planes or text scrolls across the screen. Plasmas work differently and don't require any compensating technologies. In fact, pixel response isn't even listed among a plasma TV's specs.

The best way to decide if you need 120Hz technology or not is to see it in person on a film. Some people think the technology helps make the picture more smooth, while others claim the technology can detract from the "film look," and be a distraction.

Finding the right size TV

After you nail down your choice of LCD vs Plasma, the next two factors when deciding what size TV to buy are budget (we'll get to that in a second) and distance away from the TV. Generally speaking, viewers can sit as close as 1.5 times the screen diagonal size. For you non-math professors, take the distance you're sitting away from the TV, divide it by 1.5 and you'll have your ideal diagonal TV size. For example, if you're sitting six feet (72-inches) away from your TV, the right size TV will be right around 48-inches.

Connections

You might already have a wealth of devices plugged into your current set, be it game consoles, VCRs and DVD players, or maybe you even plug in your camcorder or other video device through the traditional red, white and yellow connections known as RCA connections. All HDTVs will include composite inputs, which hook up older devices, but many HDTVs come with new connections like Component video and HDMI connections. HDMI, which stands for High Definition Multimedia Interface, conveys all the digital video and multi-channel (i.e. surround sound) audio from newer home theater components like a high-definition cable box, DVD player or game console using a single cable.

When buying an HDTV, ask yourself: how many HDMI devices will you be connecting? The aforementioned DVD player, high definition cable box or satellite TV receiver? A high-definition video game system? A high definition camcorder? A streaming media component such as an Apple TV or Netflix box?

If you've got the cash, avoid the "that's really all I need now" syndrome. Even though technology is constantly shifting, you'll be keeping this TV for a long time. If you hear yourself saying "that's all I need now," think about an HDTV with more HDMI inputs than the set you're about to settle on.

Most HDTVs offer at least two HDMI inputs. Our advice: get one with at least three. Who knows what HDMI gadgets the future will bring that you'll be drooling after?

Of course, the number of HDMI jacks is superfluous if you plan on connecting your HDTV to an A/V receiver. The receiver's number of HDMI inputs now become the issue.

Price

You'd think budget would be the first question you'd want to ask, but bear in mind you're going to be looking at your HDTV likely for multiple hours a day for many many years. Analyize exactly what kind of buyer you are. Are you looking for the latest-and-greatest TV where price is no object? Do you like extras like internet connectivity and multiple inputs? Is a middle-of-the-road set ok, where you get an adequate balance of form and function? Or, are you strapped for cash and just need something to replace a dying TV? Be sure that if you're a budget buyer now, that you're not going to be adding components in the future, nor will you miss those extra features.

Spending a couple of extra dollars will not only get you a bigger set, but probably more HDMI jacks and/or better video processing. Digital HDTVs often have trouble with unstable images such as fog, fire or water, which can look digitized as the screen wrestles to render them accurately, as well as skin tones in close-ups. Extra processing makes all these difficult-to-render aspects smoother.

The best time of year to buy a new HDTV is January/February just before the SuperBowl, or September/October. These are times when stores try to sell off existing inventory just before new fall sets arrive for the holiday season, then again right after the holiday shopping season and the annual Consumer Electronics Show, when most manufacturers unveil new sets that will reach store walls in the spring. You may even find a bargain by buying a floor sample during these transition periods.

Marketing tricks

You will be bombarded by a lot of  HDTV specification data, which companies use to try to differentiate their product. While they my sound important, marketing terms are largely hogwash.

1080p vs 720p

These two numbers indicate the highest resolution a TV can deliver, expressed as lines of resolution – 1080p indicates 1,080 lines, 720 indicates (duh) 720 lines. You'll often see an HDTV described as 1920 x 1080p, which indicates total pixels – each line of a TV is comprised of pixels. Multiple the two numbers and you find a 1080p HDTV has more than two million pixels, a 720p set a little less.

The "p" stands for "progressive scan," which means a TV scans and displays the picture in the fastest and purest form possible.

Why should you ignore these numbers? Nearly all HDTVs from the major manufacturers offer so-called "full HD" 1080p on all sizes of their HDTVs, certainly all HDTVs 50 inches and larger. Some smaller and less expensive HDTVS (yes, even a 42-inch panel is now considered small) are available at 720p, which is fine and might save you a couple of hundred dollars since below 50 inches, we find it difficult to discern the difference between 1080p and 720p, especially from a distance.

Energy

You'll hear that plasma TVs use more energy than LCD TVs. Technically correct, but misleading. An LCD TV drains at a constant rate regardless of what's on the screen. Plasmas draw power depending on what's being displayed – brighter scenes draw more power, darker scenes less power. Over time, plasmas may cost a bit more to operate, but we don't find the difference worth fussing about.

Burn-in

Plasma HDTVs used to suffer from this problem in which the ghost of an image stayed behind on a screen, especially static images such as static logos or program guide grids. Used to be a problem – it's not any more. Any sales person trying to steer you to an LCD HDTV by using "burn-in" as a wedge should be ignored.

Screen life

You'll see HDTVs with life spans rated in hours – 60,000, 80,000, 100,000. This sounds as if your TV may die in a few years. However, do the math and you'll see it's a selling point for manufacturers that doesn't really matter.

Let's say the HDTV you're considering has a rated life of 80,000 hours. If you watch your HDTV eight hours a day, 365 days a year, that's just 2,920 hours and means your TV will bring you high definition happiness for more than 27 years – and that's only to half brightness.  You can safely ignore the rated screen life number.

Extended Warranty

Save yourself a few hundred dollars. HDTVs don't have any moving parts, so if anything will go wrong with your set it will happen sooner rather than later, i.e., well within the manufacturer's warranty period. We find buying an extended warranty on an HDTV is a complete waste of money.

Looking for some recommendations of TVs to buy? Check out some of our HDTV comparators.

 [Guide originally authored by contributor Stewart Wolpin for Obsessable, small photos via Lee Jordan, William Hook, and Robert Scoble]