This really depends on who your application is built for and your organizations goals. However, I tend to believe that release notes need to be a concise listing of important key additions, enhancements, or fixes that are included in the particular release.
Sometimes a simple dump of the bug tracking system information is enough, other times, I find that they need to be refined.
The key is that typically Release Notes are believed to be the "Hey look at what we did" type listing of changes.