For people new to linux I recommend ubuntu as the best distribution. I find it easiest to maintain and it has a huge amount of frequently updated repositories for extra software. The deb package system is easier to work with than red hat's RPM system, especially if you are new to linux and just want a 'click and go' UI.
It may not be "the best" for hard core users, but it gets the job done and does it very well. I prefer it over the other distros even though I am a long time linux user.
The major problem for people switching from windows to linux is that it is not windows. No matter how good the linux distro is, most users have never used, or even seen an operating system other than windows. Microsofts dominance is just that strong. If you have a problem with windows, you just talk to one of your friend or co-workers and someone will be able to fix it for you. If you have a problem with linux it is much less likely you have a friend who knows enough about it. On the other hand, if you are not too lazy, the linux forums already have an answer to almost anything you may want to ask. I find the ubuntu official forums extremely helpful.
Good luck