Are you already happy with Ubuntu or you need another suggestion?
I'll say, stay away from Ubuntu in an office environment. It'll bite you in the long run.

Go for
openSuSE or SuSE. And yes, do remember what LittleFella wrote in his first post in this thread IF you select Ubuntu.
openSuSE is free and the most reliable Linux distro available on the planet Earth as far as my experience is concerned.