Just putting this out there...
But I've had my iMac since early 2006 and well, I plan on having it until I graduate from college in 2012. Currently I'm upgrading it's Hard Drive, Processor and network card to bring it up to speed. So rather than buying a new computer I decided to invest (+ a ram upgrade I already completed) about 300 dollars on my 4 year old computer. Some people think this is silly, but for someone in my economic situation and trying to lengthen the life of his computer, such a question as whether the next generation of iMacs will have USB 3.0 or not is a great and valid question from the thread starter.
Personally... when I get my next computer, which will be a mac, in 2012, I will be buying top of the line again, and again looking to use my computer for an additional 5-6 years.
Cheers!