@Demz... I believe that the sun will change color one day. However, I also believe it's a few million years in the future.
However, metaphorically speaking, I think JosephV understands.
@JosephV, I haven't had experience with either of those two.
From what I see of XOS, however, it will be the same as CentOS, based on RHEL, with all that implies (in other words, older packages.)
Blag might suit you though. I've played with it from time to time and it seemed stable.
Alt seems to be a Russian distribution--if you can't speak the language, I suspect it might be harder to get help.
Though it uses RPMS, it doesn't seem to be Fedora based (I'm not sure if that's an issue or not.)
I think, in the same way as Debian's stable version, if you choose something with the stability of RHEL, you will lose some of the ease of installation of the latest and greatest desktop packages.
For what it's worth, I find that I can get almost everything installed on CentOS 5.2. I cheat a bit and run a minimal text mode Ubuntu install in a VirtualMachine, then use Ubuntu's alien package to create rpms. I've only done it for a few packages, but it's worked each time, though sometimes I had to create symbolic links from an existing library. (For example, it might look for something called lib.1.0 and the CentOS version had 1.0.4.) So far, I've gotten away with it. (I don't do it that often though, I think I've only used it for BSDtar and one or two other packages.)