I have just added the fifth update to a question that I first posted more than 6 years ago. Since then it has become a tradition to revisit that question and 'maintain' it because I feel like it provides a really nice reference regarding a specific area of interface design.
I am interested to find out from the community what are some of the outstanding questions and answers that you have come across, so that I can add them to my favourite list and use them as references in design decisions (when there's nothing else to go by from the users).
My criteria would be that the question is well researched, contains a variety of good answers, and is up-to-date (i.e. contains latest information based on current trends and answers provided).
One might be tempted to think that protected questions fall into this category, but not all protected questions fit this criteria.