I find it humorous when people say they don't care about Smart TV platforms and only want the best picture. Sorry to break it to you but all the high end TV's with the best picture come with superfluous Smart TV platforms tacked on. It's just a given nowadays.
I have the 55" Samsung F8000 LED and have been enjoying it ever since I brought it home in July last year. CNET considers the F8000 to be the best LED of 2013 and you can get it at a very affordable price since the new more expensive curved 2014 models are coming out soon. My F8000 still to this day blows me away with its picture. Simply a treat to watch any content on it.
The F8000 is at the top of the picture quality list along side the Samsung F8500 plasma. So if your budget is 3K then you should choose between these two guys, no point in looking at other LED's since the F8000 tops them all in picture quality. Same with looking at any other plasmas.
If you're video gaming, the F8000 may be a better choice due to the lower input lag and no possibility of image retention but if you want the most cutting edge picture quality, the F8500 may be the better choice. The F8000's black level should be on par with your 5 year old Samsung plasma. But of course the F8500 goes much deeper.
The F8000 uses very little electricity and does not get hot in stark contrast to the F8500. I do hear that the F8500 has some potential panel buzzing issues but you're going to want to weigh in on the pros and cons of each technology LED and plasma.
You can't go wrong with either the F8000 or F8500. They are both at the pinnacle of their respective technologies and should keep you very satisfied until OLED is matured and more affordable.