The most advanced computer that it is possible to build with the matter and energy budget of Earth, would not be capable of simulating a billion humans and their environment, such that they would be unable to distinguish their life from reality (20%). It would not be capable of adding any significant measure to their experience, given MWI.(80%, which is obscenely high for an assertion of impossibility about which we have only speculation). Any superintelligent AIs which the future holds will spend a small fraction of their cycles on non-heuristic (self-conscious) simulation of intelligent life.(Almost meaningless without a lot of defining the measure, but ignoring that, I'll go with 60%)

NOT FOR SCORING: I have similarly weakly-skeptical views about cryonics, the imminence and speed of development/self-development of AI, how much longer Moore's law will continue, and other topics in the vaguely "singularitarian" cluster. Most of these views are probably not as out of the LW mainstream as it would appear, so I doubt I'd get more than a dozen or so karma out of any of them.

I also think that there are people cheating here, getting loads of karma for saying plausibly silly things on purpose. I didn't use this as my contrarian belief, because I suspect most LWers would agree that there are at least some cheaters among the top comments here.