The best HDTV that I have seen is the Panasonic Viera range of Plasma TVs,they are priced a bit on the higher side when compared to other brands but their picture quality is the best.
Sony's latest range of Bravia LCD tvs are really good,its almost up their with the Panasonic plasmas when it comes to picture quality.They have an excellent 40 inch Bravia LCD for a little over 1.3 K.
Untill recently Samsung made some better flat TVs than Sony,so make sure you check them out too and they are excellent value for money.Philips also has some good LCD TVs but they are priced a little higher.
LG TVs are excellent value for money but most of their models are not that good when compared to other brands.But they do have a couple of very good models.