Each generation of flatscreens has taken a massive step forward in quality - not just simple tech-spec stuff like resolution, but the real things that make a difference to all your viewing: contrast ratio, colour reproduction, motion-handling etc.
The Full HD Pana would be better for all those things than your set, plus looking far more detailed with HD content.
However,in your case I wouldn't buy it.Why?
1) Because you have an excellent set you're enjoying
2) Even better flatscreens, at even-more competitive prices, are mere months away. They'll have better spec (including true 24fps support etc) and the best will have boosted performance compared to the 2007 crop.
And who knows who'll get it spot-on for spec/price/performance this year? We should start to see the first next-gen sets around March time, and will bring you all the updates on models and pricing as they happen, here in our TV news section