Size. This is where most people start their search. First you need to be aware of how the TV is going to look where you place it. If you have a small room for example you might want to get a smaller screen size. This will save you money as well as give you a better viewing experience. If you have too big of a TV for the size room you have it will not look quite as crisp because you are sitting so close to the screen. This seems obvious to most people, but you would be surprised how many people think that bigger is always better. Just make sure you have the space if you are going to go big.
Type. There are two major types of high definition TVs –LCD and plasma. An LCD TV is based off of the same technology that most modern computer monitors use. LCD stands for Liquid Crystal Display. However, a plasma works by vibrating gas particles inside the TV. Plasma TVs usually have a higher contrast ratio and are typically brighter than an LCD TV. LCDs are starting to catch up though. The best way to decide is based on what size TV you’re considering. For smaller sets, LCD is usually the way to go, and for larger sets, plasma would be the better choice. You can do your own research as to how exactly the two technologies differ.
Supported Formats. HD video generally falls into two categories – 720p and 1080p/1080i. In order to get the maximum experience from your TV (and especially your Blu-Ray player/gaming console), 1080p is the way to go. Most HD broadcasts are currently in 720p or 1080i, but this could change in the near future. 1080p is the highest available HD format and therefore provides the best picture quality.
Contrast Ratio. The contrast ratio on a TV is the difference of the brightest color on the screen to the darkest color that the set is capable of producing. So a higher contrast ratio will result in a richer picture. The brights will look brighter, and the darks will look darker. Always shoot for the highest possible contrast ratio in order to maximize your viewing experience.
Sources. Connecting an HDTV to an analog cable signal will not yield very good results. Be sure to stop by your local cable company
, pick up an HD set-top box, and sign up for HD digital service. Also, if you want to take advantage of of all of the capabilities of your HDTV i would recommend getting a Bluray dvd player.
Those are pretty much the basics and the most important things to look for before you purchase an HDTV. I hope it helped.