I have a 60" Pioneer Elite Kuro plasma in my den which is about 7 years old and will be very sad the day it finally dies. But when it does, I may get a 65" to replace it. But it's on a big wall and my couch is about 12 feet away. I've always been the mindset of bigger is better for tvs.
Plasmas are the way to go. Kind of in the same boat as you. Mine is going on close to nine years old now and it's finally starting to get a little wear to it. Going back to Plasma, picking up a new Samsung 51" tomorrow.