Even in these modern times, LED floor lamps are tricky to find. We, however, found one by Adesso, the Eternity Floor Lamp, which incorporates 20 white LEDs. So what can you expect from an LED floor lamp? Well, white LEDs will emit a concentrated, bluish-white light. So these lamps are great for accent lighting. As far as energy goes, these lamps use about 2 watts or 90% less power than an equivalent incandescent.
These lamps are available here at Amazon for $80.
Update: New high-power LED lamps have now been released.