Safe comfortable housing, good food, clean water, hot showers, nice neighbors, great schools, thirty hour work weeks, all sorts of travel options...
All our cities should be like that.
We have the technologies to quit fossil fuels without going back to the stone age.
I think the most important step forward is to build attractive affordable cities; places where automobile ownership is unnecessary and it's easy to find a job that affords a nice place to live.
Next we need a society that educates and empowers women. Sex education should be realistic and practical and birth control easily available. That's how human populations are stabilized.
The current human population being what it is I no longer believe we can quit fossil fuels without nuclear power. A purely "renewable energy" economy isn't able to support the affluent lifestyle many people are now accustomed to, and might not even be able to feed eight billion people or more.
I think the most dangerous fuel is natural gas. There's enough gas in the ground to destroy the earth's environment as we know it. Yet too many people perceive gas as a "clean" fuel and good "backup" power to their solar and wind energy fantasies.
In reality natural gas is merely a slower poison than coal. Both will kill a world civilization.
Keeping some cities viable as the climate heats up and the oceans rise is going to take some hard work and a lot of energy. Reconstructing and relocating coastal cities is going to be the hardest work. Keeping the air conditioners running and the toilets flushing in places like Phoenix or Las Vegas is going to take some serious energy.