(it is, isn't it? :-) )
So, yes, we are moving on from our 10year experience with gentoo, and are searching for our new environment. From my personal experience I would say debian stable - any hard evidence to support the claim? Server OS statistics? Statistics for stableness? Bugs? Any white papers showing debian's superiority?
Not hard research, but I'll mention that one huge advantage of Debian is managing updates. Being able to get all security updates by typing "apt-get update; apt-get dist-upgrade" is fantastic. It lets me manage quite a few servers in different locations with very little work, and with great confidence that the updates will work properly. When considering other options be sure to look at how OS updates are managed, in particular security updates, and think about how much time it will consume.
----Scott.