Given the scope of the changes, it might have been reasonable to go directly to 3.0 :)
Microsoft has decided the next version of its Silverlight Flash-competitor is more worthy of a 2.0 moniker than a 1.1 one.
On November 29, Developer Division General Manager Scott Guthrie blogged that Microsoft has decided to rechristen its next Silverlight release as 2.0. Microsoft plans to make a beta build of the next version of Silverlight available under a “Go Live” license in the first quarter of 2008, Guthrie added. (A Go-Live license allows users/developers to begin deploying applications in production based on the beta.)