Found answer for your question at :

http://hometheater.about.com/od/hometheaterbasicsfaq/f/htbasicfaq5.htm

"A. Let me start off by saying that any modern television can be used in a home theater system. In essence, if you already own a good, working, television that has at least standard audio and video connections in addition to a standard cable or antenna connection, you have at least a basic way of viewing television and DVD images. The question is whether you need to upgrade to a more advanced television, or, in home theater lingo, a video display device.

Don't Get Bogged Down With The Techie Stuff

Here is where consumers get bogged down with the terminology and potential choices. Where once there was only the good, old-fashioned 25-inch tube TV, now consumers have the choice of not only a dozen sizes from 27-inches to 73-inches, but also have to choose between tube, plasma, LCD, rear projection, and front projection.

The size of the television or video display device you get really depends on the size of the room environment you will be using it in and how close you will be sitting to the screen.

However, the decision as to what type of television you get is a little more complex. However, no matter what type of television or video display device you purchase, make sure it is high definition compatible, even if you don't access to high definition programming yet; this will change very soon.

With specific reference as to whether one should get a television-type video display vs a video projector, the main factor you have to take into consideration is whether you intend to watch a lot of television programs vs DVD movies.

Factors To Take Into Consideration

Important factors to take note of when considering a video projector vs a television-type video display include:

1. Video projectors do not have RF cable or antenna connections like a television has. However, if your cable or satellite box has either S-Video, component, and/or DVI (for HD components) connections you would be able to hook them up to a video projector.

2. Video projectors have a very limited bulb life. In other words, if you are watching TV on your video projector about 3-4 hours every night, you would have to replace the light source bulb about once a year at 200-400 dollars a pop.

3. Due to the very large screen sizes used in video projection, standard TV or satellite do not look as good as they do on standard large screen television. In addition, VHS looks very poor, due to its low resolution.. If you have HDTV-cable or HDTV-satellite , you would get much better results.

Ideally, video projection really best for viewing DVD movies and, if you desire longer bulb life, limit your viewing to about 10 hours a week and your projection bulb will last about two years.

If you are looking for a replacement for nightly TV watching, it would be more cost effective to buy a large screen rear projection television, LCD, or Plasma set rather than a video projector."