We all know that the next update will be July-September, and the iMac's will have a new GPU, and all will have i3/i5/i7's (dual for 21.5 and quad for 27)
However a few times USB3.0 has been mentioned: and the answer has alway been "not until 2012"; but Sandy Bridge will have USB 3.0 (remember this site is called mac
Rumors) (
http://www.product-reviews.net/2010/03/01/intel-sandy-bridge-usb-3-0-pci-express-3-0-and-improved-battery-life/)
So the update after the September, will be in May (8 months) and we can expect sandy bridge possessors WITH usb 3.0
And with usb 3.0 we can always dream of blu-ray in the next two updates (September and May)
The apparent May 2011 update will deserve a WWDC - in fact it may be released with the preview of 10.7 which may include support for bluray.
However the September update will be a subtle boring one
and the May/July update will be awesome