Our preference for workflow at the company is to have a single repository per project. Since we often have projects that go dormant for long periods, this keeps the version numbers (that are tied to SVN builds) more consistent to the end user when updates do occur.
Because of this, we usually like to have a single repository per project so commits to a different project will not cause a large jump in the revision of an older project when we go to update it. (IE Project 1 is at rev 3, we make 100 changes to Project 2, now next bug fix to Project 1 puts the rev at 103)
Thank you