It would be really nice when editing, if items in the "Clip Bin" would highlight once they are used in the timeline. That way, one can see at a glance if the video clip or other media has already been used somewhere.
I like this idea but I would like to see it laid out a little different. Putting used clips in Bold is helpful, but it is possible to use the same clip more than once. How about a new column in the clip bin that lists the number of times a particular clip has been used? Make the column sortable (if viewing as a grid) and this way you can not only tell whether it has been used but how many times.