I bought the 59' plasma and I am totally happy with my purchase. The big deciding factor for me was that I am a gamer. And after a lot of research it became clear that the plasma is much better for games. The are several reports of the LED having slight lag with games (MLB 11 is one that has been reported several times by people).
Also, the fact that I can get more TV for the same price also was a factor. I think that LED is nice but that it still has some improvements it needs to make. The other big factor was viewing angle which the plasma also is superior at. Not everyone will be looking at my TV from the direct angle, so that again pointed to the plasma.
Good luck and I hope this was able to help.