I do NOT agree with most of the posters here.
Siriously, everybody that had to write a .rpm will tell you that RPM based systems all sux! Centos, Fedora, Mandrake, SuSe... just don't use them at all!
If you have every tried yum, you have noticed that it's slow. I mean REALLY slow sometimes. Like when you want to setup a kernel, it can takes more than 2 minutes for yum to resolve it's dependencies on a resonably fast (3GB) computer.
Also, yum needs to download all his stupid header files one by one (thousands of them it seems), which is again very silly.
I would recommand Debian for many reasons. First of all, the security team takes it's job very seriously. They do updates very fast, and the stable version of debian is REALLY stable, simply because it's not often updated (only when there is a security problem). It took arround 3 years for the Debian team to switch from Woody to Sarge, and when you had to do the upgrade, it was done very smoothly.
It takes me each time arround 3 hours to upgrade from CentOS 3 to 4 when a customer needs a VPS. Not that I do a lot of commands:
PHP Code:
rpm --import http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-3
yum update
rpm --import http://mirror.centos.org/centos/RPM-GPG-KEY-centos4
wget http://mirror.centos.org/centos/4/os/i386/CentOS/RPMS/centos-release-4-3.2.i386.rpm
rpm -Uvh centos-release-4-3.2.i386.rpm
yum install glibc glibc-common
yum install kernel
rpm -qa|grep kernel
rpm -e kernel-2.4-wathever
yum upgrade
cd /dev && ./MAKEDEV tty1 tty2 tty3 tty4 tty5 tty6
Yesterday, it took me nearly the time to watch the film "SE7EN" with my wife to have all those little commands done... Silly !!!
dpkg/apt has nothing to compare with yum that TRIED to copy apt. They clearly didn't succeed fully. With apt, it takes FEW SECONDS to do an update of the package list after a change the repository list.
FreeBSD and Gentoo are both very nice distributions, having things source based is very nice because with that, you have all optimized for your processor. But it takes too much time to do updates, and it's sometimes very risky (the port tree is sometimes broken, with major programs not working anymore (in my mind I remember a problem with libtool for example)).
Last point: most will tell you "CentOS" because this is the most wide spread in hosting environement, (because it's what most control panel support, like Plesk, DA, cPanel, etc.), but that doesn't make it any better.
Thomas