The Pansonic is recognised as the best Plasma that you can get, however the Pioneer models are also well respected.
The highly acclaimed Panasonic model is also available as a Toshiba version, which is basically just a re-badged Panasonic.
The Toshiba can currently be purchased from Richer Sounds for £2999 which is an absolute bargain.
However, this based on the old 'series 4' Panasonic and as the 'series 5' is now out, there are less and less stocks of the old model.
Currys were sort right when they said 'progressive scan', but wrong when they said 100hz.
CRTs are 'interlaced' where as Plasmas are not. The signal from your DVD player is interlaced, so the Plasma has a built in de-interlacer outputs a progressive signal to the display.
If you connect a 'Progressive Scan' DVD player to the Plamsa, you bypass the internal de-interlacer and use the one in a DVD player.
But, its not 100hz, thats for sure.
It should also be noted that whilst the Samsung you have seen is undoubtedly excellent value for money, its not particularly brilliant.
If you were seriously interested the Pansonic or Pioneer would be the best choice for picture quality, but they lack things that you would expect for a 'Television'.
If you want more info about this, there is a forum dedicated to 'Plasma and CRT' on this very site.