So there's another thinky post linked around, namely Not your granddaddy's Iowa...
which includes much thinking about the effects of the Eugenic Wars and WW III.
I'm the first to admit that I never really worked with these wars, but OTOH there are things that aren't completely round for me in the argumentation.
* The Eugenic War itself. It's all over the place in Star Trek what exactly it is: http://en.wikipedia.org/wiki/Timeline_of_Star_Trek#Eugenics_Wars_and_World_War_III
"First Contact" is the one movie that used the theme, so it might be canon that Earth was devastated at that point. The original references don't necessarily add up to this. I like the idea of Cox' novel that the Eugenic War happened in the 1990's (which is the first, specific time reference given TOS about it) but behind the scene, though I never read the novel. I just think it's a clever way to deal with a war in a time we already passed. The danger of dating Sci-Fi too close to one's own time...
* Let's assume we really had a big war of apocalyptic prospects. Humans had to unite against the Augmented - yes, they probably would. But in many conflicts, after the unification due to external pressure, new conflicts develop once that external source is gone (think WW II and the allied nations). Europe united after WW II (and it took some pains and about forty years) but did not after WW I - in fact, the catastrophe of the first war was the direct foundation of the next war. So just because you went through major disaster together does not automatically unite everyone in one happy party, it depends on all the details that happened before and during the conflict.
* Then "First Contact" is a very good example how contact would probably NOT work out, at least when you believe this scientist regarding the impact of direct contact:
"During contacts between different human cultures in the past it didn’t matter whether the ‘discoverers’ met the ‘discovered’ close inshore or on land. In both cases the roles mentioned were the same. For the ‘discoverers’ the discovery far from their home proved their superiority, correspondingly for the ‘discovered’ the fact, to be confronted with strangers on their own territory, proved their inferiority. In all historic cases the discrepancy regarding the technical level of transport was interpreted by both sides as a sign of superiority and inferiority respectively.
Much more probable [than a positive scenario] would be a global existential shock which would lead to the collapse of many social, religious and political institutions on earth. And this is independent of the motives, goals and technological capabilities of the extraterrestrials."
(source: SETI and the Consequences
(PDF, p.5); German articles by the same author: 1
The author scientist is rather concerned that this might happen to us, so he suggests we move our outposts and satellites as far out into space as possible, because the farther the contact point is away from your home, the less frightening first contacts will be. Landing with a spaceship in the middle of unsuspecting, poor, post-catastrophic humans might not be a good idea.
* Regarding the future: Starfleet is often supposed to be completely multi-racial - nothing in canon ever showed this, IMVHO. We mostly see ships with humans, with a headquarter on Earth (soCal, even ;). Vulcans have their own ships. Other races have their own fleets and agenda. In ST VI the Klingons comment on the Federation being a Homo Sapiens Club and despite the various aliens, it sure looks as if humans call the shots rather often, after starting out (if you believe ENT which I don't necessarily do) as the bad-behaved kiddie that lays the Federation foundation in the end. I see the main species having their own headquarters per planet, their own fleets that all somehow are in one Federation, but not necessarily ONE fleet.
* The Federation will have to find some smallest common denominator, but we don't know how it looks like and AFAIS each planet will have a lot of possibilities and leeway for "local" politics. As we do in Europe right now, a constant battle between national and international interests with quite some energy put into the details, and many people of the involved countries unsatisfied with the results.There will be a broad variety of lifestyles but very likely not all in one place.
Dang, I wanted to write story instead of meta but I love all these ongoing discussions - even though it seems I'm not half as optimistic as the general Star Trek fan.
Here, have a classic DS9 quote at the end:
"Let me tell you something about Hew- mons, Nog. They're a wonderful, friendly people -- as long as their bellies are full and their holosuites are working. But take away their creature comforts... deprive them of food, sleep, sonic showers... put their lives in jeopardy over an extended period of time... and those same friendly, intelligent, wonderful people will become as nasty and violent as the most bloodthirsty Klingon. You don't believe me? Just look at those faces... look in their eyes.
*hearts DS9 for its realism*