Here's an iMac touch concept with Siri !
http://vimeo.com/40725761 9to5Mac have posted this cool concept video of a touch screen iMac with Siri integration. The concept was sent to them by Joakim Ulseth.
I would love to see this happen, with all my iOS devices around me in the office, I constantly find my self trying to touch my Mac's screen ! (and yes I know that Steve Jobs dismissed the idea, but then again Apple has a long history of changing their minds!)