My friend is going for that new LED lighting. Costs a lot more up front, but should pay for itself in electrical power savings, and will probably outlast the owner!
LED is way of future. Sodium is still viable and the low pressure sodium lights still are most efficient lights made, at 200 lumes a watt they are about twice as efficient as high pressure sodium ( abt 100 lumes/watt) but low pressure produces a yellowish light. Best LED's made today approach 150 lumes/watt with 100 lumes/watt being more the norm. Incandescent bulbs are in the 8 to 15 lumes/watt range. Mercury vapor about 40 to 50 lumes/watt.