At the risk of being pedantic, I just want to clarify some of the terms used in your post.
LCD = liquid crystal display. This is not a lighting technology, but is instead the image-forming part of the display through which light shines. All currently manufactured Apple displays use this technology (as opposed to CRT, DLP, or OLED).
LED = light emitting diode. As these are currently used in computer displays, these are not used to form an image. They are used as the light source, particularly in newer displays over the traditional CCFT (cold cathode fluorescent tube) technology, which is basically a long, thin, and fragile "light bulb." LEDs are solid state, have much longer usable lifetimes, are more color-stable, and have better efficiency than CCFTs.
The two technologies, put together, form the majority of the display itself. The LEDs shine light onto a reflective backing, which then bounces the light through the LCD, producing the image you see.
From what I can tell, the 17" screen comes in two types: (1) 1680 x 1050 CCFT, and (2) 1920 x 1200 LED. Both are LCD displays--it is the lighting technology and resolution that are different.