Going Paperless - Document Management System

I have been looking document management system (DMS) so that we can go paperless, as much as we can. We have to use paper, considering our goverment and various other complainces require us to maintain document in paper form. I am currently evaluating following DMS:

These are opensource and stable products. However, it takes little effort to install and customize both of these for following reasons:-

Once I implement one of these successfully, I would post details. Meanwhile, we have done following to reduce paper usage:

With these small changes, we are already seeing benefits. With DMS, I can imagine life would be lot easier when it comes to maintaing, reviewing and sharing the documents. Please share your experiences, perhaps there is a better system I can implement easily.