What distro?

If you're used to Ubuntu, you'll probably feel right at home with Debian. Most of the commands that you're used to (e.g. apt-get) will continue to work, most of the files will be where you expect them to be, and everything is extremely stable.

The main differences seem to be:

1. Debian does less hand-holding than Ubuntu does. For example, Ubuntu suggests that you install mostly unrelated packages when you mistype a command. Debian will simply tell you that you mistyped a command. Ubuntu's approach is more helpful to newbies. But once you know your way around a server, you might prefer Debian's blunt simplicity.

2. Debian upgrades have historically tended to be smoother than Ubuntu LTS upgrades. However, I'm not sure whether I can expect the same level of smoothness with the switch to systemd in Debian 8.

3. Debian is known to contain less "bloat" than Ubuntu, although the difference is minimal in server installations.

4. Debian's support cycle (roughly 3 years per major version) is shorter than Ubuntu LTS (5 years), so you may need to upgrade more frequently.

5. Currently, Debian 7 contains slightly older versions of most programs than Ubuntu 14.04 LTS because Debian releases new versions in odd-number years. If you really want the latest and greatest, use the dotdeb repository.

If it isn't broke don't fix it, unless you have a lot of time on your hands and don't mind screwing up your servers I wouldn't risk changing anything. 12.04 is supported until 2017.

That said, I've always beena bit partial to openSUSE it's quite different from Ubuntu/Debian, has a short support cycle (18 months), I've never used it on a server before but it's fun on a desktop/laptop I find it's very compatible with whatever hardware I've thrown it on even newer hardware.

Thanks very much for your suggestions.

The project I'm talking about is a hobby and I enjoy playing about with stuff so may change to Debian or Suse.

Also thinking about giving Nginx a go instead of Apache.

Thanks again!

Distro hopping is seldom productive (especially so with a server) - if you're looking for new and interesting, stick with the distro you know, but add to your expertise - add nginx to the mix, or learn how to do automated deployments with puppet or chef, or add monitoring to your server with monit and munin, or master off-system backups so you have a failsafe bare-metal restore plan that works, etc, etc.

Distro's all have their own peculiarities, so instead of learning the surface of several distro's that all do pretty much the same thing, stick with one and really delve deep and master it.

I personally like CentOS due to the very long lifespan and the stability of what it has.

But there is nothing magical about CentOS that makes it run better than other Linux distros, for me it is largely because I am a fan of RPM and know RPM well, and CentOS is the distro with the longest lifespan that is both free and RPM based.

If you want to pay a license, RHEL is another option, but the only differences between RHEL and CentOS are stuff I don't use, so…

vonskippy is right, distro-hopping is fun for the home PC just to see how the different distros do things, but on the server, stick with what you already know unless it really doesn't suit your needs.

I started with Ubuntu as you did, and eventually decided to make the move to Debian. I wanted fast and stable.

And guess what? I've not regretted it one bit. Currently have 5 Debian Linodes, and love em.

I personally use Debian on all of my web servers and I would recommend that (and you might as well go with Debian Jessie since it's release is this weekend) if you're used to Ubuntu. If you're looking for something different then maybe you could try Fedora 21 Server? Or maybe try something different like go with a LEMP Stack (Nginx) instead of Apache, or even try using Nginx with HHVM (I just setup a new server for my Wordpress installs that has Debian 8 with Nginx and HHVM and my god is it blazing fast).