I guess the question should rather be: What does tomorrow's event have to do with a company that used to be known for building professional computer equipment? Somewhere, something went terribly wrong in Cupertino.
Soon, the Apple data centers will host a myriad of Windows PCs for their streaming service for games.
The rest of the servers will be busy streaming video content to their consumption devices: AppleTV, iPad and iPhone.
The Mac will only remain for the few people who write software for those iOS gadgets.
Kiss your "professional" Mac equipment goodbye, because it has lost all relevance for this "new" media corporation.
You have to blame Steve Jobs who changed the name from Apple Computers to Apple in 2007: "The Mac, iPod, Apple TV and iPhone. Only one of those is a computer. So we’re changing the name."
The same guy talked about the post-PC world in 2010.
"I think PCs are going to be like trucks. Less people will need them. And this transformation is going to make some people uneasy... because the PC has taken us a long way. They were amazing. But it changes. Vested interests are going to change. And, I think we've embarked on that change. Is it the iPad? Who knows? Will it be next year or five years? ... We like to talk about the post-PC era, but when it really starts to happen, it's uncomfortable."
Also, Apple does not use Macs in their data centers. In fact, some of their cloud services are/have been hosted in Microsoft's and Amazon's data centers.