LCDs are a better choice for the average household where background lighting is not controlled. When properly calibrated plasmas are superior, but real world people don't calibrate.
Why are LCDs more popular than plasma?
I have a rough time seeing differences in picture quality between brands and models, but the difference between plasma and LCD are overt even to me. When I go to bestbuy, fry's, etc. and gaze at their displays of flatpannels, plasma televisions just look beautiful, despite the reflections, while LCDs just remind me of working on my laptop. Is there more merit to the quality of LCD than I observe or is there some other reason LCDs outnumber plasmas?