Kantor on 02 September 2009
A 12,000 sample size might be accurate for, say, 5 million products.
For 100 million I'd rather go with manufacturer figures. This is marginally more accurate than the GamePro poll.
The ratio of sample size:install base is roughly 1:8000. This is equivalent to an install base of 80,000, and asking TEN people.
(Former) Lead Moderator and (Eternal) VGC Detective 
