Plasma screens have a better viewing angle than large screen LCD screen, and also are currently better at colour reproduction.
A lot of the actual Plasma panels are manufactured by the same companies so you will notice the same plasma specification for a lot of different televisions.
If you are wanting to be ready for the new High Definition Television (HDTV) then look for a screen that will be able to take a HDTV input - Sharper lifelike images with superb detail.
Plasma televisions are actually cheaper than standard televisions, a 42 inch CRT would cost more to buy than the same sized plasma screen!
Something to look for is the Contrast Ratio - This is basically how black the blacks are and how white the whites are. A good ratio is 3000:1.
Plasma screens are not a new invention, the first was actually built in 1964 at the University of Illinois.
Some other things to look out for are twin tuners, picture-in-picture, on-screen display and the number of Scart sockets that your television comes with.