Roger Lamb has posted an article about SharePoint objects, which must not be disposed. He also wrote about changes to SP 2010 regarding disposing objects.
- SPContext.Current.Site
- SPContext.Current.Web
- SPContext.Site
- SPContext.Web
- SPControl.GetContextWeb(..)
- SPControl.GetContextSite(..)
- SPFeatureReceiverProperties.Feature.Parent
- SPItemEventProperties.ListItem.Web
- SPList.BreakRoleInheritance()
- Do not call list.ParentWeb.Dispose()
- SPListEventProperties.Web
- SPListEventProperties.List.Web
- SPSite.RootWeb
- Problems may occur when SPContext.Web has equality to the SPContext.Web.. make sure you dispose of SPSite and it will cleanup sub webs automatically
- SPSite.LockIssue
- SPSite.Owner
- SPSite.SecondaryContact
- SPWeb.ParentWeb
- SPWebEventProperties.Web
More on his blog: http://blogs.msdn.com/rogerla/archive/2009/11/30/sharepoint-2007-2010-do-not-dispose-guidance-spdisposecheck.aspx