The "it just works" model of computing is better even when you do know what you are doing. Most people are lazy when it comes to their computers. I know I am. If the a typical user can't be bothered to update their Windows anti-virus, he won't read man pages in *nix.

I don't think Linux will take off until a major computer manufacturer gets behind it. Not just Dell shipping Ubuntu, but Dell creating its own distro guaranteed to work out of the box and keep working. Sort of a linux equivalent of Mac Os X, with one company responsible for everything on the machine.