Don't get excited, he may have been talking about the recent Mac Mini Update.
I think the Mini was a big part of Steve's statement, but it surely isn't just that. The mini is great, but not at all Apple's best selling desktop mac, let alone the entire Mac line. According to the Apple Online Store, the Mac Mini is 4th place in the top 10 selling list (which is followed by the Mac Pro in 5th place, which I admit is actually very questionable to begin with

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But I think we can all safely assume that the top 3 has merit. The Macbook, Macbook Pro, and iMacs are definitely Apple's best selling Mac computers. In fact I just visited my local SF store yesterday and those three machines are without a doubt, the most prominently displayed Mac computers in the store.
So I don't think the Mac Mini is everything Apple has up it's sleeve for the Mac. If we are to believe statistics, then we should be able to expect some more surprises for the other Macs as well, hopefully with the Mac Pro very much included. The recent Mini redesigns gives me much hope that Apple may be doing the same with the Mac Pro. In my opinion, I think we'll see some similar drastic changes in aesthetics to the Mac Pro, at the very least. I honestly didn't think of it very much of before, but after seeing the new Mac Mini, I am optimistic. The 7 year old design, as great and functional as it is, doesn't sit right with the rest of the Mac family anymore. I think 2009-2010 marks a significant and important relaunch of the Mac family, starting with the redesigned Macbook and iMacs from last year.
As glum as everyone on these forums tend to get about the demise of Apple's professional market and Mac OS, this is probably THE best time to really emphasize their computer line, as its very clear that their iDevices are producing that so called halo effect for Apple. I can speak out of experience as I've already converted many traditional PC users with iPod/iPhone into crossing over to Macs. And such, it takes really little effort, as they are the ones that usually approach me with the questions and the interest.
Hey, but that's my hunch. I just don't think the Mac Mini is all Steve told us to wait for. There's just got to be more to it than that.