Back to the OP original question ..
For Server use I would say Centos, Debain Stable, RHEL, or Suse EL, Ubuntu LTS Server
For Desktop use I would still stick with a Stable distro Like Debian Stable, Suse, or Redhat EW, Ubuntu LTS Workstation.
I wouldn't use Fedora or standard Ubuntu as a corporate Server or Workstation OS, because to me they are both development distros, used to test new software, they change and update on a fast pace, and in a Corporate environment you are looking for stability over the long term, not updating to the latest and greatest every 6 months.
I'm not saying there is anything wrong with those distro's, I just don't feel the corporate environment is their appropriate place.
One thing I have found to be hard for me and that is installing 3rd party stuff like x264, ffmpeg, vlc, etc. ( fun video extras )
This is simple in Debian Stable, but you are running a testing version. I wouldn't expect testing or unstable to have everything in place all the time. their purpose isn't necessarily stability and ease of use, they are development versions.
For Debian stable installing VLC was as easy as aptitude install vlc mozilla-plugin-vlc