Hello Gail,
I have actually been doing alot of research on this topic lately.. Some claim it to be a matter of opinion(unless you're an avid sport watcher).. Plasma has a smoother transition w/ picture flow w/ live tv. It may have more glare than an LCD if placed in an occasional sunny location however... Lcd's seem to have an almost fake crisp image that can be a tad jumpy(esp. w/ live transitions) Even w/ the higher 6ms response rate, (for smoother motion with fast-moving sports and action movies, and a higher dynamic contrast ratio on newer models) plasmas seem to still reign if you read enough reviews on them(especially from those that own both!)
Any-hoo From what iv've been researching it seems a 720/ 1080 Plasma will surpass an lcd w/ smooth vibrant transitions where lcds are still catching up w/ this! Also, Plasmas used to have a "burn in caution" where as LCD's not so much; but the newer ones are supposed to be game freindly w/out the worries!
I personally had been leaning toward an lcd.. but now (esp price wise) I'm steering toward a NEW plasma instead! (the older models not as reliable)
I hope this helps w/ your decision.. Good Luck! Chris!