Hi GregM,
This article of mine in the Axiom archives should help you
(http://www.axiomaudio.com/archives/pixelcount.html).
Keep in mind you might have been looking at so-called "EDTV" (Enhanced DefinitionTV) panels, which are not HD. They are the equivalent of DVD resolution--480p.
The best plasma displays tend to have slightly better shadow detail and blacks than LCD. Plasmas also run hot, and use lots of power but can deliver a very bright picture viewable over wide angles. Plasmas start at about the 42-inch diagonal size and larger. LCD panels dominate the smaller displays.
LCD panels typically may have limitations on viewing angles to the side, and somewhat grayish blacks, but the best ones can deliver excellent picture quality with good contrast.
Within each category you'll find significant differences from brand to brand, with Panasonic and Sony being at the top in both LCD and Plasma technologies. Dell also sells a highly rated 42-inch plasma.
Store displays will vary from good to bad, but if you hunt around, you may find one where you can make reasonable comparisons.
Regards,
