Oh sure I also run it everywhere else -- sid on my workstation, 'testing' on my home server and laptop etc. It does cover pretty much all the bases!
But, the 'stable' server is rather amazing. I (used to) get into rpm-hell with centos/redhat in a matter of weeks. Even ubuntu will break stuff more often than not when crossgrading from 'major' versions.
Debian is a great, stable distro. Even Sid, the unstable, rolling branch sees little breakage overall. Sane defaults, package maintainers who care about the minor rendering bugs in obscure packages and make the effort to patch said bugs. I'm continually impressed by the fit & finish of Debian, especially in context of how deep the Debian Archive is, with 68 thousand software packages in total.