A Siri that comes out of Beta is a killer for Google. Why? Apple's not going to put ads in it, just search and commands.
I'm not saying that Siri is a google killer. But a product that delivers the results without delivering ad revenue to Google (LIKE Siri), is exactly what IS a Google killer.
Google is an advertising/marketing company. I don't like the idea that one company controls what the majority of the world thinks the "right" answer to any particular problem is. That's a tremendous amount of power in the hands of a company that takes money to promote products and services. It's downright creepy, and I can't really understand how people think otherwise. It's the Facebook generation, I guess.