> On the Greenpeace site, they address directly the mercury issue

Yes they do:

“It’s not ideal but incandescents are probably responsible for more mercury emissions than CFLs; burning coal for electricity emits mercury, and incandescents use much, much more energy.”

Is our only viable choice really between larger mercury emissions elsewhere or smaller mercury emissions in our own house? I’m not suggesting that the first alternative is good, but the second is truly terrible.