My thoughts on TV purchasing:
Search out deals on the internet for TVs. Don't let the displays fool you, the stores will put a cheaper TV next to more expensive one to convince you to buy the more expensive one. Usually you can take a quick look at the back and see why the picture quality it different, one will be on RCAs and the other will be on an HDMI.
The best time to buy is Black Friday and the week before the Super Bowl, that is when you will get your best deals.
If you budget allows, buy a LED back lit TV. It will have a much longer life and a higher contrast ratio.
Contrast Ratio Does matter, higher the better.
Refresh rate is a gimmick, your local movie theater runs at a refresh rate of 48hz or 72hz.
Your old tube ran at 96hz or lower.
Name brand TVs and Non-Name brand TVs share most of the same parts.
Nearly all new LCD panels (all brands) are made by Samsung in Korea.
Screen Resolution makes the biggest difference in picture quality, 1080P is the current standard. Blue-Ray is 1080P, Xbox360 is 720P, Wide Screen DVD is 480P, Standard DVD is 1080i, the first HD sets were 480i. Don't buy a 720P TV over $500.
Sound may be the biggest difference in most modern TV sets.
3D is very cool, but I would wait a few years for everything else to catch up before taking the plunge.
Plasma use them most energy, are susceptible to burn in, are very heavy (real glass), and have the best true to life colors.
LCD consume little energy and do not burn in, now you can choose your back light (LED or Florescent). LED is by far superior; it draws less power, has a long life, and is dimable (improves contrast ratio).