I have been searching for months for a great 42-50" plasma 1080p tv. I finally purchased a Panasonic TH-42PZ77U for 1199.00 at Sears. Actually I originally purchased it at Circuit City for 1350 - However they refuse to match black friday sales ads (and Sears is obviously cheaper). The sale for this specific tv is good through the 17th I believe. You will have trouble finding this good of a deal on the 50" for some reason. Nobody seems to know why the 42" is so readily available for so cheap while the 50" remains a little higher (relatively speaking). Anyway, if you can sacrifice for the 42" - Sears is the cheapest you'll find for now. The picture is amazing (contrast ratio, sound, etc) - well worth it.
As I said the lady at Sears guaranteed to match any black friday ad, so I assume this would have to be company policy. My suggestion is to get the tv you want BEFORE black friday and then search like crazy for the best deal ... then have Sears (or wherever you purchase it) match that price.
As for which is best etc - look for a high contrast ratio (10,000:1), multiple HDMI ports, and of course resolution. I insisted on 1080p although you will not find that quality picture broadcasted yet. I just don't see the point in investing in a technology that will be outdated within a year or so. Hope this brief misc rambling helps and goodluck. Let me know if I can help with anything else...
If anyone finds a better deal on a 1080 plasma PLEASE let me know!!