I would love for when I receive an item (or give away an item) for that to show up as a growl in the upper left, with the icon for the item in the growl (to more easily see what was given / received).
This should also apply to the Rube (I hate not knowing what I traded away later, in case I have to replace something) - considering there is no notifications what-so-ever for what you give / get from the Rube post-trades :-(