Somewhat of an old topic, but I see nothing wrong with fission being the main power source for the human race for centuries... once we finally perfect it. A molten salt reactor running on uranium/thorium is a pretty neat idea. Sounds quite safe in theory; no pressurized water, potential for complete actinide consumption, no combustible gas production possible, truly inherent safety.
I have heard the analogy that fusion is so difficult you could have a group of PhD's standing around scratching their heads at it. Fission is so easy you can hire a kid straight out of highschool and he/she can run a fission reactor.