Best/Easiest Linux to Use

We have a new Dell 2900 that I’d like to use Linux on for cost reasons, but there are many to choose from. What we plan on doing with this server is hosting our websites as well as our email. I’m going to use Apache for websites and Postfix and Dovecot for email.

I’m going back and forth between CentOS, Fedora Core 8, Arch, Ubuntu, and SUSE Enterprise Server.

For ease of configuration and security, what is the best version to go with? I’ve looked on line almost everywhere trying to find comparisons of each and there’s no site that will list what one can do that the other can’t. What does one come with that the others don’t?