For desktops: Debian testing + pinning as needed to backports, sid, and experimental.
For servers: Debian stable + backports.
That last in particular is vastly preferable on servers to the usual "Oh, we've got to run Red Hat because it's industry standard, but we're going to have to rip out the guts and install a metric shit-ton of third-part / roll-your own / nonstandard packages, and then hope that the poor third-generation admin to inherit this cesspit can make heads or tails of it.
For servers: Debian stable + backports.
That last in particular is vastly preferable on servers to the usual "Oh, we've got to run Red Hat because it's industry standard, but we're going to have to rip out the guts and install a metric shit-ton of third-part / roll-your own / nonstandard packages, and then hope that the poor third-generation admin to inherit this cesspit can make heads or tails of it.