Recently the "Digital Television Transition and Public Safety Act" was passed. This sets February 17th - 2009, as the "final-cut-off-date" for Over-The-Air Analog TV Broadcasts. That means your 'Rabbit Ears' and the tall antenna on your roof will be useless except for lawn ornaments. To watch any TV presentation that originates outside of your home you will need new hardware. The minimum will be an HDTV with a digital tuner. The tuner can be integrated or external. If there happens to be an HDTV Transmitter close enough to your home, you can buy an HDTV antenna.
HDTV signals are line-of-sight, so if you are on the edge of a broadcast area there are Roof mounted antennas available. This is how the local broadcast network affiliates will transmit, if you still watch them. There will of course be satellite and cable available for the myriad extra entertainment venues they provide.
Some regions may need an HDTV antenna if your cable provider is slow bringing HDTV to your area or if your area has no cable. If you use one of the Satellite providers you should be in luck. They are transitioning to HDTV as we speak. Ain't Competition Great.
HDTV SPECIFICATION
The HDTV specification provides for three different types of HDTV, denoted by the number of lines of resolution and the signal type. They are:
*1080p (1080 lines, progressive scan)
*1080i (1080 lines, interlaced)
*720p (720 pixels, progressive)
Any TV not capable of displaying at least 720 lines is not 'HDTV ready' and any signal with fewer than 720 lines is not an HDTV signal. So, in order to be properly HDTV capable, a TV needs to be able to display at least 1280 pixels horizontally as well as at least 720 vertically.
The 'i' and 'p' in the HDTV specification refer to interlaced and progressive scan. The analog TV we've been watching for years is interlaced. That simply means that each frame of video is split into two fields. Each field contains alternate lines of the signal (one has the odd, the other the even) and is displayed for 1/60th of a second. Because it happens so fast, your brain interprets each frame as a single image. Progressive scan signals have no fields, they simply display each frame in its entirety for 1/30th of a second. This results in a higher quality image, particularly noticeable in fast-action broadcasts such as sporting events,
Once the decision is made as to how you are going to receive HDTV some decisions need to be made about how you will use the system. Your choices in display technology will depend on your most frequent use of the system. Depending on your interests you will want to evaluate different types of displays and/or controls.
Gamers will probably want different display qualities than a Home Theatre Buff, Sports enthusiast or Business users. Business applications such as Power Point & Spreadsheet display well with most consideration being given to the size of the audience. Avid sports viewers will need true high speed performance. I haven't been a Gamer since before Intel's P III, so their concerns will be addressed in another publication.
So what do you prefer?
A front-projection system uses a projector and a separate screen, and it projects images onto the front of that screen. This setup looks most like what you'd find in a movie theater -- the projection unit is completely separate from the screen. The projector can be placed on a table or mounted to the ceiling. The picture looks best when displayed on a high-quality screen, but a specially painted, flat wall will work as well.
Rear-projection systems look more like traditional televisions. They display images on the back of a screen rather than the front, and the projector is completely contained within the television itself. You can also set up a rear-projection system with a projector and a special screen, but the term is most often used to describe self-contained TV sets.
For that theatre experience at home, without the sticky floor and screaming kids, I prefer a front-projection DLP Projector for my Home Theatre Room. In my opinion DLP is best for Home Theatre Video's (DVD Etc. because of higher contrast and deeper black levels, Contrast (3000:1 for DLP, 1000:1 for LCD).
A projector of this type can project on a wall screen up to 120" in size with high contrast and deep black levels. DLP miniprojectors on the market are around 3 pounds. Most LCD projectors are five pounds or more. These differences are being narrowed as technology progresses. For Business applications such as Power Point & Spreadsheet display these are not noticeable concerns.
I'm a Home Theatre Buff so DLP meets my expectations. But there are other technologies with their own pluses and minuses.
Plasma Displays have great resolution and incredible color definition. With a resolution of 1366 x 768 a plasma display can give virtually a 3-D effect. This in combination with exceptional color reproduction can be quite stunning.
Plasma does have some issues though. They can be subject to 'Burn in' and there is a concern with 'Life Cycle'. At the price levels you will find in display technologies a screen that only lasts 20,000 to 25,000 hours before replacement is needed is problematic. This is possible with Plasma although NEC is working on raising their 'life cycles' to 60,000 hours.
LCD's have an average life cycle of 30,000. LCD Screens deliver a very good picture. The LCD was the first display to have 1080 line resolution. LCD is better in bright light conditions. LCD historically delivers better color saturation than you get from a DLP projector although this is a major focus of new research on DLP tech.
Compared to Plasma, LCD has slow reaction time if you are watch presentations focusing on split-second events such as NASCAR and other sports. Contrast, at 1000:1 is not great compared with Plasma & DLP. Full black is hard to achieve with LCD, black is usually a deep Gray. LCD may also be subject to a screendoor effect, at times seeming to show a division between pixels. Also a potential problem with LCD: Long Term Image Degradation. Although this would most likely happen after a comparable Plasma screen may show effects of a burn in or element failure.
There are so many factors to consider and so much information out there that many more articles can be written. So for now further research and choices are up to you.
Technology 
