For a server Debian. Can't beat almighty Debian. Unless you're gonna talk about desktops, in which case my vote still goes to the sexiness that is openSUSE .

Edit:

I just noticed you have both SuSe and openSUSE in the list. Both are the same. The only difference is that SuSe is paid because it comes with support etc. openSUSE is the free version that doesn't come with support and is more bleeding edge (sort of a testbed for future versions of SuSe).