Plasmas are in my opinion the better technology. If you really want to know why then sit tight.
Picture: Independet pixel lighting used in plasma tech. is supperior to backlight and edge-lit LCD/LED becuase there is no "halo" effect when you see black on the screen. Take a good look at the best LCD/LED Tvs and you will notice that the black levels are either a dark blue or have a gray look. Contrast ratios mean nothing from one brand ot another because there is no set standard and everyone can claim whatever they want. If what you read on paper matters, then compare this statistic within the same brand and see it for yourself.
Asthetics: I will admit that the thin LEDs from Samsung are beautifil but I'll ask you this, When is the last time you watched the side of your TV and not the front? Have you ever spent 2 hours starring at the side of a TV rather than the screen? Alson, samsung does have a 1.2 inch thick plasma (PN50B850). Sure it may nont be a 55 inch but at 50 inches and the price on this site, it beats out the LEDs in my mind. Panasonic has the TC-P50Z1(not found on this site) which is less than 1 inch thick and next year they will introduce many more 1 inch thick plasma-panels (straight from the manufacturers' mouth).
Longevity: Straight out of the manufacturers mouth, Samsung & Panasonic Plasmas have a 100,000 hour half-life and even longer lifespan. The best LEDs from Samsug have a 60,000 hour lifespan.
Refelction: Oh man, I have seen what this year's plasmas look like in bright rooms, and trust me, they have no problems whatsoever in those conditions. I have seen and LCD and Plasma TV next to each other with the sun light blasting right at them and what I saw shocked me. I could not see a dang thing on the LCD (and yes it was on). The plasma was 100 times clearer than the LCD, the LCD looked as though someone smugged gray paint all across it (lousy matted finish).
Energy: Ah, the one stat that LCD/LED legitimately owns over plasma. I'll give it to you straigh forward, not everyone watches their TV on the same setttings and not everyone cares to adjust them. Many simply set the TV up and watch it. If you take the time to tweek your TV (less than 5 minutes), you can reduce energy consumption on any technology without sacrificing picture quaility. In any case, all 2009 Plasma/LCD/and LED TVs will cost you less than $4 dollars a month (assuming you watch less than 4 hours of TV a day) on your electricity bill when the picture settings are adjusted just right. LCD/LED wil just cost you 1 to 2 dollars less than plasma on the bill. I think it's worth the small cost for a better picture.
In the end, I always recomend plasma to thouse who are not sure but for those who are a bit stubborn then I suggest you take the time to look each TV and trust your own instincts and eyes. If what you see is what you like then go for it, be it Plasma or LCD/LED.