I hate stacked area charts (2011)
I agree with the problem but disagree with the solution.  I'd much prefer removing the stack completely and using overlapping plots, like this:<p><a href="http://i.imgur.com/zO7CuQG.png" rel="nofollow">http://i.imgur.com/zO7CuQG.png</a><p>In a chart like this no data is lost in presentation.  You can easily answer questions like "when did Android overtake iOS in marketshare?" and "is Windows Phone marketshare growing or shrinking?"