It's hard to describe anything in home cinema as the 'best'. There's always other things to consider such as your budget, the type of room you're using, the type of things you are watching etc.
However, if we talk about plasma TVs in general...
About a year ago, most people would say that Pioneer made the 'best' plasmas - however they would also cost you more. Unfortunately Pioneer are leaving the plasma TV market and it might be hard to find any of their plasma TVs in the shops now.
That just leaves Panasonic, LG and Samsung as manufacturers of plasma TVs.
Panasonic would probably now be seen as the market leader, as they have a history of making good quality plasma TVs. So check out their latest models to see what you think.
However the newer models by Samsung, and especially LG, have been getting some good reviews and so they are definitely worth considering.
Hope that helps a bit.
Does anybody else have a view on this?
For more information about plasma TVs, take a look at the plasma tv guide.