Basically there are two types of HDTV's.
- Note there are two types of LCD's
Old LCD technology comes with CCFL back lighting, These will slowly start to be phased out.
New LCD technology comes with LED lighting and is utilized by back,side or top and bottom.
When they coin the term LED, It is in terms of the lighting method.
*Note OLED's work on different principles and they are not viable right now, so don't confuse it with LED.
There are pros and cons to both to determine what is best and ultimately it's what looks good to you.