John,
I have used a high pressure sodium light successfully for three years now. It is on a GFI and has only tripped once. The lights are about $80 at Lowes/Home Depot. I have never had to replace bulbs. They do cast a yellow tint though. They should cost about $40/year if they are on a photocell/timer. I also have an RV florescent low wattage bulb that runs off of batteries when the A/C power is down.
