Well that was my point, that finding a human habital planet within 1000ly is astronomical, and in reality even that is too far, it would have to be inside of 100ly minimum. Obviously finding something we could terraform is more likely, but thats a whole new set of problems, and terraform is probably what well need to do. Sure on earth we adjust our environment to suit us, but anywhere you go here you can stand in the open and breath. Sure technology can create places where we can, survive, but all that will ever amount to is a sparsely populated outpost. Terraforming is also turning out to be a larger problem then originally thought. Take Mars for instance, seemed on the surface a reasonable thing to overcome, but now, not so much. Because of its very weak magnetic field there really is no chance of turning it into a human friendly enviroment, any effort we make to get an atmosphere going will get blown into space by the solar wind, not to mention the problem of radiation.
Careful about that line of reasoning. Take ourselves 500 years into the past, and they (Europeans) thought the same about Africa. Hell, go back 20,000 years to the time without technology and the same can be argued about present day Europe and North America.
Just because something is difficult, does not mean it is impossible. It is rather difficult keeping suburbs running. They are poorly suited for manufacturing and poorly suited for agriculture. The only benefit of them is that they are good places to live, with a nice population density to meet with people, combined with open space to relax. However, being far away from work would make them rather difficult to maintain, so they didn't really develop until sufficient technology and a rich middle class developed to be able to afford the expenses and logistics to enable them to come into existence.
It is foolish to presume something *exactly* like earth exists elsewhere simply because there are too many factors. If it is close enough, it is good enough. Slight modifications can be made to suit us, much like how slight modifications on earth have been made to suit us. I don't see anything wrong with having self-enclosed heavily insulated homes, and requiring you to wear special clothing to go outside. Take North America or Europe in the winter. It seems exactly the same; you can't step outside naked for too long without hypothermia. Add some clothing, and you're fine.
For extraterrestrial colonies, only a fool will refuse all but the most perfect of planets. (They honestly have to be more perfect than most of Earth to properly suit humans) The vast majority of people have been living in suboptimal environments all of their lives, and simply modify it or ourselves with technology to compensate for it. I don't see why that approach is impossible for a colony.
The temperature ranges are quite acceptable. The gravity is a bit more uncertain, for all we have is the mass of the planet at 3 earth masses. We don't know the density to be able to determine its surface gravity. But hey, because it is massive enough and the temperatures are in the right range, we should have the two main factors down already. Temperature, and Pressure. Building sealed environments (akin to Biosphere 2) should be able to provide us with a good place to sleep and rest without a sealed suit. Assuming the pressure is acceptable, you don't even need a bulky space suit to maintain the pressures; all you need is a wet suit to keep out the cold or a cooled suit to keep out the heat. If the temperature is in a nice limit, you theoretically only need is a breathing mask if you are wandering outside the dome.
Oh, and for Mars, you really only need a pane of glass to keep out most forms of UV light. Glass and most plastics are opaque to UV light, and you really have to work hard to let them through. (this is the reason why blacklights are expensive) The other radiation (cosmic rays) may be a slight problem, but underground cities are not unheard on Earth, so that may be used if you are too lazy (or cost prohibitive) to build a dome encompassing the colony.
Well in the context I was using it I would be referring to a sentient life like us, capable of technology, and I would agree that we are not the only sentient life on earth. But really, regardless of how intelligent a dolphin gets, in its body it will amount to nothing in a civilization context, like you pointed out. So like I said and you seem to agree, even if a planet is perfect, and has sentient life, a sentient life capable of civilization is still unlikely. So if you consider the odds of finding an earth like planet and again the odds of a technological species evolving on that planet I dont think its a stretch to think there is no such place within a 1000ly, and even though @10000ly the odds are better, thats way outside of any possibility of us or them ever meeting, they may as well be in another galaxy.
Well, you are setting the bar rather high. From what I understand is that you are suggesting intelligent life can only evolve on a planet exactly the same as the earth, which is clearly not the case. We are only adapted to the conditions we are in because we adapted to the conditions, not the conditions adapted to us. Other planets with less than ideal conditions for us may have a thriving civilization which is excellently adapted for that.
Anyways, 1000 LY is a very large region. 109 stars lie within 20 LY. (note, we already found a habitable zone planet within 20 LY and we barely have done any searching) 260,000 lie within 250 LY. 600 million stars lie within 5000 LY. The numbers you are throwing out are absurdly underestimating the number of stars in the galaxy, or you are assigning absurdly unrealistic numbers to the Drake Equation.
Here is a bunch of galaxy maps I found a long while ago.
I did recently see a show where they were talking about the 'galactic habitable zone' I remember why the core was considered uninhabitable, but there was a reason why they think the outer edges are too, just dont remember why.
Metallicity. Lack of supernovae explosions nearby to seed it with enough metals to form rocky planets.
When people say theres four hundred billion stars in our galaxy it must be full of Aliens, I always thought "but wait" everything in the core you can pretty much eliminate, its just way too violent, so that eliminates, I guesstimate well over 50% of the stars in our galaxy. Then theres the multiple star systems, binarys and such, which account for most of the stars, and I think those can be eliminated as well... thats a whole lot of stars writen off before we even start.
Don't get too trigger happy eliminating stars from consideration. Binary stars are perfectly capable of having habitable planets. Just have to take into account that there is another massive object nearby, so stable orbits are only close to a single star, or farther out orbiting both. You'd have to look at how the stars are orbiting and what type of stars they are before you eliminate them.
Also, life forming in the galactic core is improbable, but not flat out impossible. So long as there are no supernovae events nearby, they are safe. Considering how most of the core is made up of older stars (ones that won't go supernovae), so long as their star formed semi-recently, or even migrated into the core, they stand a rather higher chance at forming suitable planets due to the metallicity content, and due to longer lived stars because of higher metal content (it gets in the way of H atoms, slowing down nuclear fusion a bit).
Now consider also "how long will a civilization survive?" based on our civilization it isnt going to be very long, but I'm sure not all species will be so self destructive as we are, and some will be even more so. That there is sentient technological life in the universe other then us, I agree. I would even suspect sentient techno life, at this time, in our own galaxy... but I would suspect they are very few, and very far between. I would be surprised if there are more then half a dozen such life forms in our galaxy, at this time.
Well... The "how long a civilization will survive" is more accurately put as "how long a civilization broadcasts wide field radio". If they cease to broadcast radio, it's as if they are dead to us. We can still contact them via other means, but they won't be visible to us.
However, what about the civilizations that expanded to other star systems? After they have built up a second star system, they are virtually invincible to mundane events. No asteroid is going to destroy both star systems at the same time, interstellar wars highly favor the defender, etc. After a civilization buds off to multiple star systems, they become neigh impossible to eradicate.
. So now we have to go outside of 100 light years, or over 2000 years travel time, and more then likely outside of 1000 light years, if were lucky, thats 20,000 years travel time. Now thats just finding a planet 'capable' of supporting complex life, the odds of such life developing are again astronomical. 
Humans
but I still say the odds are astronomical.
