We use either Centos or Redhat Enterprise. The 2 are very similar and does not make a difference to us which one we use. Any other operating systems we have not used personally on our servers and do not see the need to.

We use Centos for our web servers that run cpanel. We also never run into any trouble. FreeBSD is also a great OS with a good package manager

CentOS for the most part

We use Debian, but we've used CentOS, Fedora and FreeBSD in the past. CentOS is great if you like RedHat style tools (rpm's).

Fedora was great for test servers but proved to be a pain on production machines. Its changing too quickly and its clearly meant to herd corporate users to their commercial RedHat products.

All linux systems are 99.5% identical but the management tools differ slightly. FreeBSD was great but just too much of a headache to administer. Wonderful performance on FreeBSD though.

Debian is the easiest to admin and update (IMO), but has the steepest learning curve of any Linux. Well worth it though.

Ubuntu server is very popular nowadays but I've never used it personally. That may prove to be the best of both worlds, easy and foolproof.

We use Server 2003, Server 2008 and CentOS 5. All cpanel servers are running CentOS as well as Ubuntu Linux which comes on dedicated.

For my vps I had no choice. I wanted a managed package from the zone folks and turns out you can have any os you want as long as it's centos. kind of crazy, doesn't make too much sense to me, I guess it's just easier to manage.

I use fedora at home and was hoping to get that, but i would have had to get a non-managed package and i'm all about offloading my grunt work to the host.

is there much of a difference really between the os on a dedicated server and a vps? is there stuff that comes by default on a dedi that you don't get with a vps?

I like CentOS and Debian