I'm asking myself this question but I got no answer, I would like to hear your comments.

Myself I like Fedora distribution as it's always reviewed after every 6 months, but this is a problem for a server, as one wouldn't like to change his server after every 6 months, (or every 6 months upgrade to new fedora is not supposed to cause problem in a production environment?)

Maybe Ubuntu has fewer updates than fedora? And what is happening to ol redhat series RH8, RH9 etc?(Since fedora became famous I've lost connection with that series...)Maybe CentOS which takes the shape of RHEL is good for server as it has fewer reviews(i.e.it is stable much more like RHEL?)

Please advice as I'm stuck there...

Cheers,
Stefano

Try Debian, last debian version got out after 2 years, it's stable and much used by servers...Just try it and after tell us if you're satisfied or less...

I think the obvious choice is Centos. Since I haven't used enough different distributions and I don't know your expertise level and I don't know what you want to use the server for, I can't guess whether Centos is the best choice, which could be different from obvious choice.

I've never even download a Fedora installer, so I don't know what assumptions the installer makes about home system vs. server. The Centos installer very much assumes you are installing a server. The Ubuntu installer very much assumes you are installing a home system. If you are experienced in Linux, I'm sure you can blast right by any such assumptions and install a home system with Centos or install a server with Ubuntu. All the packages and options are supported either way.

But if you are less experienced, you won't even know the names of the things that should be added and removed to correct the installer's assumption of home system vs. server. For that reason, I would suggest selecting Centos rather than Ubuntu for a server.

Yep;
Centos is the free version of RH Enterprise Linux. Highly recommended if you want a (real) server.
Fedora is the bleeding edge release from RH, basically research, and more home/client oriented.
The old RH8, RH9 series was discontinued at v9 , which is when RH split into RHEL and Fedora distros.

I use ubuntu server, because I am familiar with debian distros. I would prefer to use centos in the real world though.

Well there's Centos / RHEL, there's Ubuntu Server / Debian, and probably others.

In the end it probably boils down to personal preferences.
CentOS is basically RHEL without Red Hat trademarks, and without Red Hat support.

Ubuntu is based on Debian, but, similar as Fedora, has a release cycle of 6 months.
Ubuntu also offers a Server Edition, equal release cycle as the regular Ubuntu, if I'm not mistaken, but every once in a while (think every 2 years), they have an LTS - Long Term Support Edition, which several people choose to use as server for next few years.

Debian is highly stable (that's not to say the others aren't stable), Debian Stable releases tend to be outdated with some items, due to their release system. However so does current CentOS / RHEL, which comes with PHP 5.1.6 by default and OpenOffice.org 2.4 as example, when you can get PHP 5.2.9 already as well as OpenOffice.org 3.1

Best to do in my opinion is to take each of the above four mentioned distros and see with which one you can work.
If you prefer rpm based distros, then go for CentOS / RHEL, prefer deb based, then of course Ubuntu Server / Debian

I use all four of the above distros.
CentOS @ work on all of our servers, and therefore using it also as office desktop from which I'm writing this, throw inbetween some RHEL servers of ours in USA, whereas private I use Debian and Ubuntu, simply as I prefer them in general, and would also prefer to use them in our work environment, but alas, use of CentOS has been implemented years ago when I wasn't here
Ah, and previous company I worked at, absolutely everything serverwise was Debian. Nothing else, pure Debian area, and we had a few

I wouldn't choose any such distro for a server.. Much more suited to server capacity are distro's like Archlinux or Gentoo. I set up servers using Mandriva and Ubuntu and when it came to number crunching they were hands down beaten by a minimalistic distribution. As for CentOS, I have to work on CentOS driven servers from time to time and I have come to dearly hate them. And when combined with Plesk, it truly becomes a slow nightmare.. Keep to these bloated versions if you must, but I much prefer the speed and capacity offered by a minimal distro.

Ubuntu also has a release cycle of 6 month for new versions. That is not the same as updates !

Ubuntu LTS server versions are supported for 5 years (6.06 till june 2011, 8.04 till april 2013). And it will get updated when required.