I like the first, I would essentially use this one
I dont like the 2nd one, percentages are less informative
The 3rd one is ok, but the non cumulative representation is harder to judge than the cumulative one (1st graph)
also, it is surprising to not see "price drop" on ur graph, particularly the 100$ one of the PS3 in november 2007 (40gb)
my prediction : march 2010
(I saied end 2009 but it was before the WW xbox360 price drop)
(sidequestion : do u do these graph online on VGChartz ? if yes, how ?)
Time to Work !