There is one feature I would love to see included, and that was a bookmark-feature. Something similar to the favourite-feature; but without the counting and without the implication that you found the question particular useful.
I have been using the favorite-feature to mark questions to revisit, but as I also use it to mark questions I found particularely useful (it's intended use?), things become a bit chaotic. So it would be very useful with a seperate bookmark-function, just for questions you for some reason would like to revisit later.
Another great feature would be a follow-feature, that tracked changes to a question - like new answers and new comments. It would be very useful when one encounter a great question with as-of-yet no answers.