The 60 million units for the Wii by end of 2008 John Lucas prediction sticks out most in my mind as the most absurd prediction.
It will most likely go on to be the least accurate prediction for the Wii on this site, even less than the equally absurd 30 million units sold considering the final tally will be under 45 million (closer to 43m), with a 2.4m/month production rate.
Predictions explaining inflated numbers by claiming production will be increased to 3m/month in 2008 also get a booby prize.