..Anyway as I always say, just like audio, video is subjective as well and I respect that difference....
Actually, there is rational explanation why audio quality is subjective - anyone above 20 is partially deaf and won't hear certain frequencies and this only worsens as one gets older. That's why every person hears music/sound differently and will prefer equipment with a sound signature that suits his hearing spectrum. That's why it's best to carefully audition audio equipment before buying.
On the other hand, video quality is not subjective because everyone (who has 20/20 vision or is wearing specs to get 20/20 vision) has the same level of eye sensitivity. Also, video qualities like brightness, contrast, color accuracy etc. can be easily measured with hardware. So, it's easy to quantify picture quality.
Here's an objective report and it favors plasma for picture quality - LCD-Plasma Display Technology Shoot-Out
The models compared of course are 2008 models. Since then LCDs, LEDs have improved no doubt but plasma's have improved too. So these results should hold good to date.
So, it's a well known fact that at the same price point a plasma screen will have better picture quality than an LCD screen. That's the reason why every reviewer keeps a Pioneer KURO plasma as reference display to use it as a benchmark to compare other TVs with.
To the OP : Dude, don't get confused by all the posts here. Simply get an LCD because it's very impractical to use a 720p 42" plasma as computer monitor. Trust me, I've tried.