Also keep in mind that although the database is registered as versioned, that doesn't mean you always have to have child versions. If 90% of the time none of the files are needing edits, you can set up the security as Robert discussed, basically having it be read only for all but SDE account and/or the owner. Then when you are getting ready to make changes, create a version (only takes a few seconds) giving your designated edit the rights to edit. Do your necessary reviews of the data, and when ready to publish, do a reconcile and post so others will see the updates from default. If you know that it will be a while before you need to make anymore changes, you can always delete the child version after the reconcile/post and after an admin compress, you may even get back to state zero.
Personally, I would always recommend making changes thru a child version and not the default because it gives you the chance to reject conflicts if needed. That is not to say that I haven't made a quick, simple change directly to the default (for example a change to an attribute).
Also, take advantage of creating an historical markers that can basically show a virtual cooy of the database status at the time you made the connection.
