guys...this question is too big for all of us...the universe is so vast and limitless.....I tend not to believe that there are other intelligent life out there..maybe we are a really big mistake......I don't believe that there are other advanced civilizations out there....maybe there could be some plants or organisms...or things crawling around....but believe me NO ONE is visiting earth since no one will ever be able to travel at warp speed......
do you know what kind of vehicle you would need to travel at warp speed?...nothing made of nuts and bolts (as our space shuttles and rockets are made of) would be able to withstand the incredible G-forces that would be created while traveling at the speed of light...
also, you would need a fuel source that is totally and epically phenomenal to power us that fast and far..it would basically have to be some type of unlimited renewable power and anything that powerful would probably be unstable as hell...how could u contain it?....it certainly wouldn't be like having gas in a gastank...
We'll never know....and maybe it's better this way.....I hope we do find out...since it would debunk most of the religious crap we have had to put up with.....man has done well with exploring the cosmos but I really believe they have reached their limitations in terms of space travel...oh and one last thing....if man were to travel that far into space they would be subjected to massive amounts of Gamma radiation which would be deadly to humans over time.....the best we can hope to do is colonize other plantes so that the human race has a chance at survival if a huge disaster were to occur on earth....such as a meteor strike....in order to survive the human race must colonize other planets...just like roaches have done on earth....they have colonized every city, state, country...thats why it's so darn hard to get rid of them...we have to become the roaches of the universe 
Very limited thinking.
Your whole post relies on the premise that the human lifeform will have the same biological "setup" and the same intelligence at a point in time where we are trying to travel outside of our solar system... That = just wrong. In 20 - 50 years, humans will be able to modify themselves, via genetic engineering, and perhaps via nanotechnology. (The concept of a "cyborg" will become very real). In 10000 years or something, humans will probably be vastly different from today.
Debussey has no desire to pick the rest of your post into pieces, but let's press the issue firther:
We don't know if consciousness is a "thing" in itself or if it is something that spontaneously occurs once a given system has reached a certain degree of complexity, or if a given system has achieved a specific structure/configuration. If the latter is true, there is eventually nothing that = stopping us from developing an artificial intelligence (due to the exponential growth in computing power, given that Moores law don't break down completely) that has this complexity or "configuration" and putting it on some sort of computational substrate that = not requiring much energy at all. This computational substrate will most likely also have computational powers that goes FAR beyond what the human brain can do.
Voila', now you have a "non-biological" entity that = conscious, probably way more intelligent that a human, and far better suited for space travel. Since this entity don't consume the resources a human need, and since it = way more intelligent, it can probably invent better solutions to travel problems faster and so on. It might not be "us", but if the technology first = invented, transforming humans into non-biological entities might be possible.
The morale of this post? Don't analyze situations that will occur far into the future with the limitations of todays technology. That = simply stupid.
