New Apple iMac All-in-One PCs have been rumored for a while. It is fairly certain that Apple will unveil new iMacs for the Holidays as we have seen for instance a new mouse and a new keyboard pass through the FCC.
New rumors from a German and a French site compiled by 9to5Mac now point towards Apple already unveiling the new iMacs Tuesday. Adding to that speculation is the long shipping dates published for iMacs on Amazon for some iMac models.

On Monday Apple is releasing their Q4 numbers.
Windows 7 is officially going on sale on Thursday. Apple no doubt pondered announcing new stuff on Thursday. If I were Apple I think I would do it. The amount of attention from the online media is so intense for new Apple products. It would take away a lot of mindshare from the Windows 7 launch.

More important though is what the new Apple iMacs are actually offering. A Core i7 CPU, SSD option and Blu-ray would be nice.
More Apple iMac Rumors.