Whenever I edit an item or page, I get a big fat notification balloon at the top that says something like:
"✓ Success 𐄂
Tracker item 79663 has been updated"
It annoys me that it consumes precious vertical space and that I have to manually dismiss it each time by clicking the tiny tiny "𐄂" button. Thanks for confirming that my changes have been successfully saved, but I shouldn't have to do an extra click to clear out the notification so that my contents show up un-shifted.
Ideally it should show up as an z-order overlay (maybe semi-transparent, 90%?) above the page header, and automatically fade out after 7-10 seconds, especially if there has been mouse (or keyboard) movement detected on the screen (i.e. if you want to make sure the notification remains if the user had walked away from the computer during a long process, then you can keep the notification shown until there has been some mouse movement).
Of course this only applies to success/confirmation notifications, where no user action is needed, not error messages or question prompts.