I think Siri is cool. But just to keep things in perspective, on my Galaxy S2 I can say "navigate to wherever" and it will fire up Google Maps and give you turn-by-turn voice directions with a moving 3d map. I can also send text messages and emails and it will solve math problems, define words, play music, call contacs etc... Where Siri shines is in the calendar/ reminder area, "remind me to take out the cat when I get home" etc...
You can bet that Google is working feverishly to improve their voice control, so they will probably catch up in that area soon. So again, I think Apple did a great job of implementing Siri, but I don't see it as anything earth shaking or industry changing.