@john, i have been caught before using seperate charts to look at the picture as a whole (mrstickball and about the XB360 to XB comparison...though i had to at the time because the charts were not working and Jp XB info was missing)
If you notice in EU the PS3 would be vastly ahead because the info is skewed with the 'others' section where PS3 was released well before the PAL areas.
But that is not the point. The point is you can't add up the seperate differences by region to get a picture of the whole, you can use it to say "here the PS3 is tracking ahead of the GC" or vice versa, but you should look at the All section for a WW comparison, because that shows you how many consoles were sold irrespective of whether they were available in all regions.
The GC was actually released in September for Jp, November for America, and the following May for elsewhere, so that gives it an advantage when looking at seperate regions because in Japan the launch hype had time to die out before christmas, and in Eu the GC (at 9 months old in Eu) would be just finishing christmas,(admitedly the chart shows a rather unnsuccessful xmas, but there is a rise).......so extra sale there thus giving it one region (America)with launch+xmas crushed together (restricts sales because they would be high at xmas whether it was launch or not) and TWO regions where, by this point in it's life, had both christmas and launch seperate.
What you should do to compare the two systems, is look at WW sales, for which the PS3 is ahead by 500k.
