Debian has the reputation of being more something for advanced Linux users, who know how to work with the console and know how to manually configure the kernel. I haven´t heard of Gentoo so far. Here in Germany SuSe is the best known distribution, you can get the professional version (which I would advice to buy) for about €70,- . It comes with a fat instruction manual and several thousand programs, including various server software. Their default desktop enviroment is KDE, but you can as well chose to use Gnome or a non-graphical interface (going through a console, similar to the old MS
DOS for slow, old computers or pure servers).