Rumor has it the canon 3D is gonna spoil Nikon's D300S party. Canon will supposedly also announce the T1/2000D with video to compete against Nikon's video-less D3000. So looks like canon is looking to score big after Nikon's recent beatings.
I think a canon 5DmkII body with an APS-H sensor (the 3D) at a D300 price would sell very well. If the rumor is true then it makes sense as to why Nikon's "only" upgrading the D300 to an "S". The D400 isn't ready until March 2010 and they don't want to hear all the crying about why they don't have an answer to a "canon 3D" with video.
Imagine the confusion at the camera store when you call and ask about the D3000,D300,D300s, D3,and 3D!