A desktop has to be easy to use !
And Linux is waiting for its breakthrought, still because there is a big gap between any distro and Windows when it comes to useability.
I am personally using Debian and RedHat right now, both work really great, but I think most Windows users won´t be happy with Debian, maybe a bit with RedHat.
All the setup thingy and the rest is quite complicated, so it is more work then running Windows, that is why many people like SuSE Linux, in the end .. it is not as stable or bullet proof as others, but it is quite easy to use
I know for the "experts" the developement of Linux from a real hacker OS to an Windows style OS might be uncomfortable, but this is what is necessary to become a bigger community ..
We will see what happens next