I love this quote and just saw it again on the Evidence 2013 conference site (http://www.evidencelive.org/student-delegates)
"Half of what you are taught as medical students will in 10 years have been shown to be wrong.
And the trouble is none of your teachers know which half"
Dr Sydney Burwell, Dean Harvard Medical School. In: Evidence Based Medicine, Sackett et al, 2000: 31.