iLife '07 is not guaranteed to be released in January but there's a good chance it will be.
i doubt there will be any improvements to the iMac since no new chipsets are expected for January.
if it doesn't hurt you to wait, i don't see why you should rush into anything right now.
I really don't think that would work, because while the iMac uses mobile/laptop processors, the Core 2 Quad is a desktop processor, and a pretty hot one at that. It would not fit well in an iMac.If you look at the frontpage, there are pland for a "Core 2 Quad" chip, which I think would be ideal for the iMac.
i typically recommend to purchase ONLY the day of or after an update.