I really don't think energy is the issue slowing down our advacement, so much as our contentment as a species. An overwhelming majority of advances in technology and medicine has come as a direct result of us sometiems wanting, but usually NEEDING such advancements. Right now, we've kinda grown confortable with where we are and what we have. Of course there are still areas to improve and people willing to work to improve them, but there are fewer people driven to change things for the better, since they're okay with what we already have.

As energy goes, I'm all for nuclear. storing waste products is a relatively simple matter to handle compared to issues with other energy sources, and it puts out a ****load more energy to boot.