Good Drupal distribution to start with Workflow? Is there a  better Drupal 7 distribution that I can start with, for an enterprise website which require to have workflow support?
Note: I don't know what you mean by "better", and also I don't know what you are comparing to.

NodeStream is my employers distribution. We base nearly all of project off it, and we try to keep much of our work in the open, to ensure that everyone can use it. We have support for the Workbench module and its workflow.

There was a presentation about how we work with NodeStream and built on top of it during the Barcelona devdays 2012, but as far as I can tell, no videos have been posted from there yet, so I can't link to it.