Check out
www.linux.org or distrowatch.com Those sites have info on the Linux flavors.
If you like RedHat, go with CentOS which is a clone of RedHat Enterprise Linux. Stable and security updates are regular. Their Fedora distro has a short life span, so it doesn't do well for a server. I run CentOS and have been happy. Though I wish Caker would make CentOS 4 available, as it comes with SELinux modules.
If you are just looking for LAMP, I have to agree on Debian. What makes Debian such a great release as a server, IMO, is that Debian as a very long life span. They do make regular security updates, but they haven't officially released a new Debian version is a LONG time, nor are they requireing older Debian versions to upgrade or be SOL.