Plasma = Darker, uses more juice, and generates more heat. Some folks like the look better, though.
And it's cheaper!
IMO I'd research brands more than type of TV.
I really like the CNET reviews, very informative about what you should and shouldn't worry about; what's marketing fluff and what isn't.
TV Reviews: LCD TVs, flat-screen TVs, plasma TVs, 3D TVs - CNET Reviews