For the best, listen to NacDoc. Pioneer makes their own and they are the best, but, prepare to pay for the best.
Plasmas are emissive (emit light), while LCDs are transmissive (work by selective blockage from a back-light). Because of this, LCDs blacks will never quite be black, but dark gray. Also, light and color dynamic range is typically greater with Plasma's.
LCD is a good, long-lasting technology, but in the larger sizes (36" +) are still not the best bang for your buck. They are still a bit on the pricey side, with the price divergence starting at around 32". LCDs do use less power and generate less heat. In your typical viewing room, ambient light levels should not be high enough to cause problems with LCDs.
Today, reliability should not be an issue with either one. I suggest that you stick with the more known brand names (Pioneer, Samsung, Sony, Panasonic, etc.) for a whole variety of reasons (quality, support, reliability, etc.). Yes, most of the display panels are made by one of 3 major manufacturers, however, the control electronics are not.
Enjoy,
Rich P