http://bits.blogs.nytimes.com/2009/04/23/undoing-meg-whitman...
Third cause successes can hide failures rather well. Companies can succeed despite their absolutely atrocious leadership - not because of it.
Both she and Carly Fiorina were two of the worst things that could've happened to eBay and HP respectively (Meg Whitman for both).
They are nasty pieces of work.
Balmer is another example - he is single-handedly going to destroy a $200 billion dollar corporation and no one is stopping him. Hell they'd save a lot of money by making me CEO :D.