Is there much difference on problems between plasma and LCD TV's? My 3 1/2 year old Zenith Z50PX2D blew up Sunday and, so far, even though it's a known defective design, LG will not repair/replace it.

Nah, as long as you buy from a reputable company (Sony, Pioneer, Panasonic, Samsung, etc) you should be good to go. Both technologies have their issues. Just buy a TV that you like and fits your budget.

If you're taking about quality issues, both plasmas and LCDs have very low rates of failure.