From an overall systems perspective, the house is a closed box with a certain amount of heat energy being drained from it by contact with cooler outside air and ground, and a certain amount of energy being pumped into it from everything that consumes gas or electricity inside it, to achieve a certain average interior air temperature.
Incandescent lightbulbs are 90% efficient at putting heat into this closed box - only 2% of their output is wasted as visible light, and the balance is in other areas of the spectrum. It's not my fault that you don't have a more efficient means of moving that heat energy around - that's an application issue, not a performance issue with lightbulbs. I could put many kilowatts of incandescent bulbs in my basement, and it would be very hot down there, and cold upstairs, but I'd hit my goal of an overall average temperature (it wouldn't be evenly distributed, but it would hit the average).
I could even build a ducting system and hook up a blower motor, and create a furnace powered by lightbulbs. This furnace would be quite efficient, but very expensive to operate because electricity costs more than gas. But it would be pretty efficient. To say otherwise is silly, because we know that 90% of the energy coming out of a lightbulb is heat.
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-Scott
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