What do you think are the chances? Apple didn't bring Siri to the iPhone 4 to sell the 4S - do you think Apple could possibly do that with iMacs? Dictation is part of Mountain Lion, so it's logical to assume that Siri is the next step. Plus Macs (especially the iMac, with a constant power source) could have Siri constantly running, without having to worry about power consumption associated with having the mic always listening for the keywords. Only reason I asked is because I just recently bought an iMac - still in the return window, but I won't be by the time September 12th rolls around (assuming, of course, Apple does refresh iMacs then [even if it's a silent refresh]).