What's the next logical step in a computer interface? I used to say "Computer, show me the money" to open Quicken back in pre-OS X days. More of a gimmick than anything else, but imagine if the Finder and maybe even other apps became "speakable."
Me: "Check mail"
Computer: "You have nine new messages. Would you like me to read them?"
Me: "No, thanks."
(clicks on an email, reads message)
Me: "Reply to this message"
Computer: "Type or speak?
Me: "Type"
type-type-type
Me: "Computer, I'd like to add a photo of the kids to this email."
Computer: "iphoto has 6,813 pictures of the kids, which one would you like?"
Me: "One from the birthday party last week."
Computer: (a strip from iphoto appears) "Here are 23 from last week. I've highlighted the one where your wife fixed the red eye. Is that the one you want?"
Me: "Yes, that will be fine."
Computer adds the picture to stationery in the email, other pictures go away.
Me: "Send the email"
Me: "...and order me a pizza."
This kind of thing can't be too far off. A 75 mhz Performa could do it in a rudimentary way. Imagine what a modern Mac may be able to do. "Speakeasy" has a nice ring to it.