I know others have alluded to this, but I think it is a VERY important thing to factor in making iMac predictions...
The Back To School Mac offer goes until September 21.
I think this annual offer helps Apple clear a lot of their aging product lines. In previous years, these offers included free iPods (iPods that, not coincidently, were at the end of their product cycle).
Now lets be rational and think like a business...
Would Apple want to release a new Mac product towards the end of the Back to School offer?
Many people would return the iMacs they just bought to get the new one's. So Apple would get returned computers they were just trying to get rid of.
As far as I remember, you have 14 days to return.
So, I think it would make more sense for the release to be at least 14 days after September 21.
Doesn't this make sense?