We have a Panasonic Viera, that we got back in 2007, and love it. If I had to get another Plasma, I would say Panasonic would be my first choice, unless OLED sets come down in price in the next two years, than that will change. Panasonic is still pretty much king for Plasmas, even after CES 2012.
The Samsung PN51e8000 is showing as a possible contender. The best thing to do, is go out and look at them. Find someplace that will let you play with the sets, not stand there and treat the remote like the holy grail and not let you look at features, or play with settings. They can always turn them back up after you leave. I would definitively change the extreme settings that they have their sets at in the show room, due to the majority are either too low, or too high in turn, making one set look worst, another look better.
Worst thing to do, is to go someplace and look at a wall of tv's under flourescent lighting, or turned so far up, or really low in a low lighting showroom. And do not go during the weekend in the middle of the day, when every other shopper is out looking, go during the week, or go in during the day during the week if you can take time off from work, so that you can go in when no one else is in there in crowds.