Will Vista be good for open source?

With Windows Vista somewhere on the horizon (of course no one knows how far of a horizon) open source advocates have a unique opportunity.

One object to switching to Open Source systems is the transition cost to move everyone to a new OS or OpenOffice instead of Microsoft Office. Well it seems like everyone is going to have to transition to a new version of Office with a brand new control interface (the ribbon) and it seems as if everyone is going to have to learn Vista at some point.