Whats best an LED or LCD TV? Whats the difference?

We need something on the 40" – to 50" range.We have lots of windows, we watch sports (pixeling?) and HD cable TV. Is Hz really mportant? Any perered brands? -Thanks

Suggestion:

M explained it beautifully. LEDs have a better image quality and are brighter, they alos have a better contrast ratio. The Hz is how many images per second the TV can produce (240Hz = 240 images per second) There are some great brands but I'd go with either Sony or Philips.