I used this website (including and especially this thread) while researching my new TV, so I feel like I should share my experience. I'll try to keep it brief.
I've always had LCD tvs in the past, never plasma, but I've always been told how much better plasmas are. I decided to give it a shot and bought a 59D6500 (upgrading from a 40" Sony LCD). I absolutely loved it. The black levels were amazing (although the white levels are terrible compared to LCD...), fast motion looked phenomenal, etc.
After about a week, I noticed the buzzing. It got extremely loud at times. So loud that I could hear over the sound of the show I was watching, even with the volume at 20. I've heard some of you say that you can just ignore it, but I simply couldn't. It sounded like high voltage power lines in my living room. After reading that several people have tried exchanging them multiple times, only to get buzzing tvs over and over, I decided to return it and go back to LCD.
Now I have a Samsung UN55D6420 LED LCD. Not only is it silent, the picture quality (including the black levels) is easily just as good as the plasma (in my opinion). I actually like it better, because whites actually look white instead of light gray like on the D6500.
Maybe I'm just not a plasma person, but I gave it a try. Hopefully this helps someone else that is currently looking for a new tv.