I dunno. The more I try to use it, the more I find myself a little disappointed. I have a Ford Fusion, and I get a ton of work out of the voice recognition system in that car, which is Ford SYNC by Microsoft. Now, that system's far from perfect, but I find it to be better at basic speech recognition and reliability than Siri is.
And I think the bigger problem is just the lack of functionality. I don't know why they allow Siri to do basic things like check the weather or do an internet search that you can do quickly already on the phone, but NOT things like turning your Bluetooth off or adjust the brightness of the screen.
Q: How much memory do I have left?
A: I'm on it...would you like me to search the web?
Q: Show me my pictures...
A: If you like, I can search the web for "my pictures"
Siri doesn't understand what I want because Apple didn't want to program her to be a true utility assistant on the device. I want Siri to make simple the things that are more complicated on iOS, not just offer a "cooler" way of doing things that are already easy. Of course, all of these things are possible for the future, but I really wouldn't recommend Siri as a device selling point to anyone because there isn't much new here that I've found a use for. Even BlackBerry devices can do things like audio Google searches, or voice dialing.