Earth First!  

We can always destroy the other planets later.

I was always partial to Venus first.  At about 50k feet, the temperature and pressure is nominal, and the atmosphere is a treasure trove of resources.  A floating city that feeds modified chemosynthetic organisms from the trace sulphur dioxide in the atmosphere, would be much easier to sustain than one on the surface of Mars, where there's not much atmosphere, or particularly one on the Moon or asteroids, where there isn't any.

But, no one asked me =p

_most of it has proven to be unrealistic and not achievable at least not in a near future_

that is SO wrong.
you must not be paying attention..

Picking out a couple of the more difficult developments and accusing sci fi of underperforming isn't really fair.

There's a lot of great stuff that's been done, and is presently on the make.

Including all three of those you mention specifically.

I mean, <a href="https://www.treehugger.com/aviation/worlds-first-flying-car-let-rich-people-live-out-boyhood-fantasies.html">we got flying cars!</a>  How cool is that?  Star Trek communicators, medbay (surgical robots, and so much medical tech it's mind-boggling), and actual real good stuff, like this here series of pipes that shoot our messages back and forth.

Yeah, me also, although it'd be just me at this point.  I'm a bit long in the tooth for space adventures, so they'd need to have it down for me to be able to undertake it.

One of the neatest things about colonizing Venus, in addition to the superlative conditions for floating habitats, is that one of the worst gasses in the atmosphere, as far as people breathing it, is sulphur dioxide, which is the essential chemical food of those deep sea vent ecosystems we've been finding around the world.

Additionally, many of those ecosystems are in high temperature environments, at enormous pressures, and made of tasty seafood.  Some of the worst strikes against Venus as a habitat, is that the lower you get in the atmosphere the higher the pressure and temperature get.

Animals that can feed on the sulphur dioxide and strip from the atmosphere, are adapted to high pressures and temperatures already, and tasty, are about the perfect starting point for terraforming the place.

I just think the serendipitous synchrony of need, potential, and ability to actually go there and do something like this is more than coincidence.

I think it's destiny.

Still gonna wait for comfy chairs and room service before I go, though XD

Practically every word out of Musk references sustainability.  He says it's his primary motivation, and looking at what he's done, it does indicate that is what is driving him.  

Actions speak louder than words, and Solar City, Tesla, and SpaceX itself, are all endeavors that primarily enhance sustainability.