I'd say Ubunut is ^the^ best choice for Linux newbies(imho off course, I don't want to start a distro war
). On most machines, the installation is flawless and will set up a complete Linux desktop within an hour. It's Debian based and comes with Synaptic which is a graphic package manager that'll make installing new packages very easy (it takes cake of all dependencies etc.). The default desktop manager is Gnome, but you can get Kubuntu is you'd rather have KDE as defualt (using Synaptic you can also change it yourself off course).
The user community is very large and very friendly and available in most languages, so getting support shouldn't be a problem!