I havnt tried redhat, since its not being released anymore by RedHat...
RedHat has started a product in the stead of RHLinux called the Fedora Project, and I think the latest release is Fedora Core 3... it looks pretty awesome and has some nice tools for servers.
Mandrake Linux is by far the most user friendly, the easiest install as well. The latest version is 10.1 i think but im running 9.2 on my older box.
http://fedora.redhat.com/
http://mandrakelinux.com/
Mandrake i think is still my fav.