At last! Good news last night from the Internet Identity Workshop in California: OpenID 2.0 is finally final! I agree with Simon that the most interesting new thing in 2.0 is likely directed identity. And, yes, Drupal 6 already supports it.
However, one of the more interesting things (I think) is the final release of Attribute Exchange 1.0. I think attribute exchange (think profile data sharing and updating - and digitally signed assertions) represents the killer next step in online identity. Kudos to everyone involved! Time to get crackin' on some code :)