The argument about fossil fuel usage while using an LED bulb, in the context of trying to sell said LED bulbs, is irrelevant because of the fact that "Green" marketing sells. LED bulbs are on the market because they reduce consumption of electricity over time -- regardless of whether that reduces fossil fuel usage or not, the average american will see that as a "Green" thing to do. Consumers who like buying things because they're "Green" will buy the bulbs regardless of what actually happens in regards to fossil fuels. My favorite depiction of the power and ridiculousness of such marketing schemes is
here.
Good points for techies though.
edit --
Ironically enough, slashdot just pointed to an
article about how some regions may be 'powered' by
alkali fuels rather than fossil fuels. Heh.