Burn in is NOT a serious issue. First of all you will only get burn in after having the same image for at least 12 hours (who would do that?). Secondly, even if you have a burnt in image, modern plasma's will get rid of that image in a matter of minutes when you switch on another channel.
Burn in is NOT permanent. It was permanent a couple of years ago. I've recently purchased the new panasonic 42 inch plasma and there is absolutely no problem whatsoever with burn in.
Currently I think plasma is the way to go, mainly because ALL (yes ALL) LCD's suffer from ghosting. If you have a fast paced DVD on or a football match (soccer for you yanks) it is going to look like crap on an LCD (maybe with the exception of premium LCD's, if you're on a premium budget). And I'm not even talking about viewing angles or contrast ratio's, which are far better on plasma's.
Having said that, there's always going to be poor plasma's and poor LCD's for that matter and I can only vouch for the new generation of panasonics.
The 42 inch panasonic cost me 2000 euro's and it's absolutely top notch on all fronts.