Bill Hobbs has a great example of how reporting can be unbalanced, even when it's true. He discusses the Battle of Midway and explains that if the press only reported the loss of the carrier USS Yorktown, Americans at home might have become dismayed. When you know that 4 Japanese carriers were also destroyed, however, it's clear that Midway was an amazing victory for America and turned the tide of the war in the Pacific.
Bill also has some incredible pictures of the Yorktown sinking, and of a newspaper front page announcing the US victory. Neither sight is likely to be seen these days.