@Ken... it is very true.... under predicting is a lot better than over predicting, as proved by the PS3 last year.
If you predict 200k and the real figure turns out to be 100k, you are 100% out, but if the real figure ends up being 300k, you were still 100k out, but in percentage it is only 33%.
At least that is how it feels in the mind... in reality as the real figure is pretty much set (ie, we don't know it yet, and whatever we predict here will not effect what the real figure is unless one of us goes and buys a few thousand consoles) and if you predict 50k above or below it is will be the same percentage difference.... it's just that because we are predicting before the real figures (wel duh, no point predicting after) we then compare the real to our predicted in our mind, rather than comparing our predictions to the real.