Volkskrant science reporter Hans van Maanen came up with a list of the 10 biggest blunders of 2008 in both science and reporting or talking about science (Dutch).
#5, on the news that drinking coffee is not bad for you:
Of the healthy men who drank more than five cups a day, 20% less died than of the healthy men who never drank coffee.
Twenty percent! But healthy men—the phrase gives it away—rarely die, and 20% of nothing is still nothing.