I think were in that technological state where multiple discs are not longer needed. They are more so viewed as a hassel than anything else. When you have a medium option out there that can hold a lot of space and make everything fit on one disc it makes everything easier. If microsoft would allow developers to make use of their HD-DVD drive that some have. Then space would not be as much of an issue.
Own: PSP, DS, Wii, PS3(20GB- Swapped w/500GB)
End of Year Sales Expectations for 2009 (Added December 23, 09):
Wii: 63 mil
PS3: 32 mil
Xbox360: 37 mil