EDTV vs HDTV
You walk into a store or take a look at an advertisement and see a plasma TV for a really great price. You look a little harder and notice that it says EDTV. So you ask yourself, what is the difference between an ED TV and an HD TV, and more importantly is it worth the extra money for the HD Television? That depends on a couple of factors, but before we get into that why don't we take a quick look at what the picture on your TV screen is made up of and what makes that picture look better. After that we will discuss where EDTV and HDTV fit it.
A TVs picture
The image on your TV is actually made up of a whole bunch of dots, called pixels. The number of pixels that make up the image determines the resolution of the image. So for example, if each row of an image has 20 pixels and there are 10 rows then the resolution is 20 by 10. To increase the quality of the image you increase the resolution, i.e. you increase the number of pixels. However, if you take a low resolution image and try to convert it to a high resolution it might not look that great. That's because the source of the image also needs to be high resolution. This is the reason we have high definition channels (the high resolution source), and if you buy an HDTV is doesn't automatically make everything look better (because you're trying to convert low resolution to high).
Another thing to consider is interlaced images and progressive images. All you need to know is that in an interlaced image, every other row of pixels is drawn. So when the image is created on your TV screen the first row of pixels will be drawn, the second row will be skipped, the third row will be drawn, and so on. In a progressive image, every row of pixels is drawn. This implies that the progressive images will look better since you're seeing a 'full' picture.
Regular TVs
So what is the resolution of a regular TV? Regular TVs display an image with a resolution of 640 by 480. That's 640 pixels across and 480 down. The image is interlaced. Before moving on to the next page you may want to check out the different types of televisions available. Have a look at Plasma vs DLP vs LCD vs CRT vs LCD Rear Projection
HDTV
In North America a High Definition Television (HDTV) can display resolutions of 640x480 progressively (known as 480p), 1280x720 progressively (720p) and 1920x1080 interlaced (1080i) (some TVs are able to display 1920x1080 progressively (1080p)).
EDTV
An Enhanced Definition Television (EDTV) can only display images with a maximum resolution of 640x480 progressively (480p). This resolution is comparable to DVD quality.
What you should buy?
A couple of questions to ask yourself: Am I looking to buy this TV because of its slim size or because I want to take advantage of the "crystal" clear images new TVs seem to offer and secondly, how much money am I willing to spend? If you're looking to buy a plasma TV because of it's "picture frame" size but are not concerned about High Definition then you might as well save a few bucks and buy EDTV. You'll be getting the slim size and 480p resolution for a decent price. However, if you're looking to buy a plasma TV because of its size and High Definition then why even bother with EDTV. I say spend the extra few dollars and know that you're going to be able to display the best possible picture that is available today and in the future.
HD sources
If you go the HDTV route then you should also consider what HD sources you'll be able to enjoy on your new TV. A lot of people see the TVs on display at the retailer and assume that when they get the TV home they'll have the same experience. This may not be the case. Most large retail stores of consumer electronics feed the TVs on display with HD signals. Once you get it home, unless you also have HD signals going into the TV you won't be seeing those crystal clear images. Currently there are not many HD sources available. There are a limited number of HD channels provided by satellite and cable companies and there are also the latest consoles (XBOX 360, PS3). So before you purchase an HDTV take a look at how much it will cost you to obtain some HD content and factor that into your purchase.
Plasma vs DLP vs LCD vs CRT vs LCD Rear Projection
If you haven't had a chance yet, you may want to have a look at Plasma vs DLP vs LCD vs CRT vs LCD Rear Projection