These are two different things. LCD is a transmissive display technology whereas LED in this context is a backlighting technology for LCDs. Compare LCDs to plasmas, but no to LEDs. It's like comparing an F16 to a Ferrari, or a speaker to a graphics card.
Traditional backlighting is CCFL, which can be compared to LED. CCFL consumes slightly more power, but offers better colours. LED offers a narrower colour gamut, a slightly better contrast ratio and worse backlight adjust times. RGB LEDs offer comparable colour to CCFL, but is much costlier and consumes more power than CCFL making it pretty much useless in its present avatar. CCFLs also offer greater brightness, as well as more gradients to brightness levels. LEDs may be the technology of the future - they're certainly not worth it right now.