Similiar to Gmail, Google Docs now lets you select a color for each of your folders to represent a folder in the sidebar and in the document list for an easy spot related documents.
Another new feature, this time available only for documents and presentations, empowers you to change the owner of a document. Unlike simple collaborators, the owner of a document can delete it and can restrict the access to a document for some collaborators. This page explains the difference between viewers, collaborators and owner. To become a collaborator and transfer the ownership of some of your documents, select them from Google Docs homepage and choose More actions ==> Changer Owner.
Google, Google Docs, New Features