Earlier quoted context omitted.
It's been a while since I've had any responsibility over servers, but Debian has always treated me well.
Ubuntu which is derived from Debian is a good choice for servers, especially the LTS editions.
I'd be inclined to give it a try (I use and love Ubuntu on the desktop), but my impression is that Ubuntu is Debian packaged for the desktop... which isn't really relevant on a server. Debian is, OTOH, geared almost entirely for the server, already before Ubuntu came along.