You know, its funny trying to speculate what is coming around the next corner. We always make our little lists, and Steve just blows our minds durring the keynote. I always walk away thinking, "damn, where did that idea even come from." Steve's capacity to surprise us is unsurpassed.
If I have to make a prediction though, it'll be new iMacs and possibly displays. Surely there will be a new piece of software, the aforementioned "mind blower".