Anthony Cerrato wrote:

That's a good point. And with the complete development of
genetic engineering (or alien equivalent,) advanced ETIs may
be able to avoid any such threats.

Of this I think the reverse will be true.  Our (inorganic) engineering while bestowing wondering benefits to many people, only mirrors great disparities between the social classes: have's and have not's.  It's clear that genetic engineering, at least for a politics as primitive and carnivorous as our own, will only serve to mirror the classes as well. There will be extensively (expensively!) engineered super-humans (Rolls Royce), and the more numerous middle-of-the-road engineered individuals and the great class of lemons.

Until we've achieved a perfect and fair ethical model, tinkering with our genome is on a direct path to Hitlerian eugenics.  We can't even equitably distribute antibiotics to the Third World and manage health care at home: imagine the can of worms we'd bring upon ourselves by tinkering the genome.

Now we might postulate that an intelligent (as opposed to wrongheaded) ETI would first hammer out its social problems before hammering itself.  But if this were true, we should probably begin STI, or the Search for Terrestrial Intelligence -- because I'm not sure we have it here at home (thus the Longevity factor in the Drake Equation).

As for immortality I used to retain some hope as well.  But check out the process of apoptosis: http://en.wikipedia.org/wiki/Apoptosis. Modern medicine appears to be learning that ongoing death is required for ongoing life.  So the quest for immortality, I think, is a LONG way off (if possible at all).