What is the minimum number of people needed to create a viable human breeding population?

Hello One and All,
A very good friend of mine recently asked me the following question:
What is the minimum number of people needed to create a viable human breeding population to avoid the problems of inbreeding? I like to open this question for discussion within our forum.

What follows is my answer to her. Any other opinions on this question?

This is indeed a very interesting question and the experts are, as always, giving us all sorts of different answers. For those of us interested in one day establishing a human colony in space one researcher has estimated that you would need 160 people and with some social engineering it might even be possible to reduce this to 80.

Anthropologist John Moore of the University of Florida came up with this number after studying small migrating populations of early humans and has developed simulation software called Ethnopop that analyzes the reproductive viability of small groups. A space trip of 200 years would perhaps take eight to 10 generations, and for this, his calculations suggest a minimum number of 160 people are needed to maintain a stable population. This would produce around 10 potential marriage partners per person.

http://answers.google.com/answers/threadview?id=378894

When the Toba super volcano in Indonesia erupted and triggered a major environmental change it has been suggested that a bottleneck of the human population occurred c. 70,000 years ago, and that the human population was reduced to c.15,000 individuals globally. It has been estimated that in sub-Saharan Africa alone the human population could have dropped at times to as low as 2,000, for perhaps as long as 100,000 years, before numbers began to expand again in the Late Stone Age.

http://en.wikipedia.org/wiki/Population_bottleneck

Other estimates suggested that the Toba catastrophe reduced the world's human population to 10,000 or even a mere 1,000 breeding pairs.

http://en.wikipedia.org/wiki/Toba_catastrophe_theory

As far as I am concerned you need a minimum if 2,000 breeding pairs to repopulate a planet like the Earth. But, yet again I may be wrong and I just plucked this answer from right out of my hat. : )

I am not really clear which of these answers are correct, In the case of eventually colonizing space I believe humans will have to resort to artificial methods (cryogenically freezing human embryos, artificial insemination and genetic engineering) to create genetic diversity.

Bye for now and best regards,

Alex