The Samsung PAR38 LED bulb produces 1,100 Lumens (the equivalent of a 75-watt bulb), but consumes a mere 18-watts, about 75% less energy than a halogen bulb.
According to the manufacturer, the bright-white light reduces eye strain and can be used inside or out (if protected from weather).
After 40,000 hours of use (1,666 days), when it's time to replace the bulb, there'll be no worries about special disposal requirements. No mercury or lead is used in these light bulbs.
LED bulbs are only slightly more efficient than CFLs (which do contain mercury), but they last longer. Still, at $60 a pop for the Samsung LED, the payback period is far too long to be economically viable for an entire house.
But if you're using incandescents now and have a difficult-to-change, but frequently used fixture (think recessed ceiling lights), the LED bulb may be worth considering.