I don't use the 3D cursor much and it usually causes more problems then it's useful to me. I know ShiftS moves it to center, but is there a way I can keep it there (even if I accidentally press LMB?)
In User Preferences you can change the assigned key that sets the location of the 3D Cursor. I would recommend setting it to
Left Click so you can still move it when necessary, but you won't relocate it by accidentally left clicking anywhere.