Although all current commercial Plasma TV's offer a widescreen format, not all of them support HDTV. Deciding if you want to buy a Plasma TV that is HDTV compatible can be a difficult decision, since Plasma HDTVs cost considerably more than non-HDTV displays because of the complexity of the manufacturing process. Plasma HDTVs require the display to be able to produce images at a considerably higher resolution than standard Plasma TV's.
Additionally, the jury is still out in regards to which format presents the best picture quality, depending on the formats of media you are viewing. If you plan to watch mainly standard broadcast television (including through cable or satellite), and DVDs, many will argue that you can save yourself a significant amount of money, and still have a BETTER picture with a non-HD Plasma display.
However, if you are planning to watch a lot of HD broadcasts (limited at this time to the most popular prime time shows on the major networks, select shows on the premium networks, and major sporting events), and are also planning long use of the TV (more shows are being broadcast in HD each year), a Plasma HDTV is the right choice.
Note that a Plasma HDTV will generally cost between 50-100% more than a non-HD Plasma TV. For example, the Panasonic TH-42PWD5UY 42-inch Plasma TV currently lists for around $3000 with many online retailers. The Panasonics TH-42PHD5UY 42-inch Plasma HDTV goes for around $5000 with those same retailers, approximately a 67% premium over the standard definition television. For this difference, you receive an increase to a 1024x768 pixel resolution, versus 852x480 pixel resolution.
No matter whether you choose a Plasma TV or a Plasma HDTV, you will still receive all of the advantages of Plasma TV over other technologies.