I used kubuntu for a while and liked it although I would highly suggest joining the kubuntu forums website because the way it installs default has a few setbacks and the people on those forums will help steer you clear of any fatal errors good luck with whatever you pick.
As far as the 'and why' I don't really have a good single reason for you I just liked the way it felt I guess <- Edit
I'm pretty happy with crunchbang so far, server setup is part of the main OS setup. Either you install the stuff to make it into a server, or you dont.
Not saying it's the best, but it's very fast and gets what i need done.