I bought a pack of three "Lights of America" LED bulbs from Costco for $17 a few months ago. I used them to replace 25 watt bulbs in two outdoor lights on either side of my garage and another in the entry porch lantern. They are warm white and 135 lumens. I was concerned they wouldn't be bright enough, but they are fine. They appear about as bright as the 25 watt incandescent they replaced. Each LED bulb uses only 2.5 watts. So the analysis is....
10 hours per day * 25 watts/ bulb * 3 bulbs * 365 days = 273.75kWh per year before
10 hours per day * 2.5 watts/ bulb * 3 bulbs * 365 days = 27.37kWh per year now
Savings of 246.37kWh over the year, 6 month payback on the bulbs. Or another way to look at it is that 246.37kWh saved will take me about 850 miles in my LEAF.