We are rewriting our desktop application and we are thinking of improving the error handling and error notifications. Currently, it is based on modal dialogs. But we have a lot of errors like "You cannot add a new item. You have exceeded the maximum number of items." with only one button in the message - OK. What I was wondering is there a better way do display these kind of problems? I read in About Face that we should get rid of message box that don't give the user any choice only have one button that closes the message.
So my question is: What is better usability - the modal dialog messages described above or a notification are on the top of the application that shows save state and notifications:
Of course, if there is even better idea, I'd like to hear about it. Edit: There is Autosave, so the user dosn't have to click the Save button and with the approach of notification area I worry that the user may not understand there is a problem with the save action.