Rare Earth – how rare?

The publication of the book, Rare Earth: Rare Earth: Why Complex Life is Uncommon in the Universe, was welcomed by many in the Creationist movement. To them, it makes the case that the conditions for life are so rare, our planet had to have been specially designed as a haven for life.

The article linked to the headline suggests that habitable zone around stars may be larger than we had originally thought.

Here is part 1 of a debate on how rare habitable planets might be, and here is part 2.