I own two plasma's and an lcd and have spent a lot of time watching a led/lcd set.
plasma's have better blacks, yes. thats true. but they also have much better shadow detail. where led/lcd sets are able to get darker than traditional lcd sets, they achieve this by giving up a significant amount of shadow detail.
the deep blacks give the plasma's more saturated colors and details in the picture. plasma's have more dynamic gray scale ranges which will help render the more "3d" effect to the picture. they also more steps in the tonal range as the difference between black and white is greater.
plasma's deliver better color accuracy as they can render deeper, richer colors, and they can blend tones better than lcds, which generates a larger color pallet.
plasma's do not suffer from motion issues like lcd sets. and plasma's also have much better viewing angles than lcd sets.
and if you plan on doing any gaming, plasma is a much better choice because of all these factors.
and i almost forgot, plasma's have longer lifespans than most lcd sets on the market. panasonic plasma's are rated at 100,000 hours. thats over 11 years if you leave it on 24/7
here's a link to read up on:
http://www.displaymate.com/LCD_Plasma_ShootOut.htm