Depending what exactly you want, CentOS is still a great choice, especially if you are also using the machine for more than set serving jobs. My understanding is, that CentOS will be exactly in the middle ground between Fedora and Red Hat. So it will be ahead of Red Hat a bit, which is a good thing if you want more current software versions. But not quite as cutting edge as Fedora. Personally, I am fully on Fedora for my development machine as I want current versions of software. I didn't have stability problems with it.
There seems to be also a (planned?) free version of Red Had, if you want complete stability and only security updates.
For any regular server I’d recommend Debian. However, on my home server, I run Arch. It’s a pain with the upgrades, but I have access to all the latest and greatest software to tinker with. Which I feel is exactly what a home server is for. :-)
The only thing I had to build for myself was an Arch install ISO with ZFS included.
I second this. FreeBSD is rock solid and extremely reliable (I have systems that are running on very old hardware and little memory, and still work fine). Arch can also pretty stable, if you actually know what you're doing and you're not doing anything serious with your server.
Switch to the LTS kernel as well if you can, i.e. if your hardware does not need the HWE (Hardware Enablement) versions. The HWE kernels are mostly for newish laptops anyway and proper server hardware shouldn't need it.