the lcd v plasma debate has changed around quite a bit. Plasma's used to be plagued by 'burning out', but these seem to be solved. I recently was in a similar position and found a definite winnner in this debate. It was the Pioneer Kuro, but it was also 2,500 for a 42inch (plasma). Being too expensive, I went through all the reviews and ended up buying the Sony V3000 (40 in LCD), its quite a set, I got it for €1800 with a free PS3 and €160 worth of free vouchers from DID electrical.
As for the full HD debate, its like anything you buy nowadays, its the latest technology but is only worth it, if you like watching alot of movies (on Blu-ray/ HD-DVD), like high definition gaming (PS3 and Xbox) or have Sky HD. If you are only buying a tv to watch NTL and watch DVD's full HD will have zero effect, so basically you dont need it.