I've recently been using Excel and Powerpoint 2007, and it's seems clear that the shapes are using WPF.
Edit - I know the shapes have existed in Office for ever, that is not my question. Look at the fill possibilites for shapes in 2007, look at that gradient fill, look at its parameters - that's the same as WPF as far I as I can see. So back to the original question, does anyone know what Office is using to do that? I'd be pretty sure that MS didn't re-invent all that graphical niceness, 3D, rotation and so on just for Office, when they have the exact same stuff in WPF already.
Can anyone confirm that office is using WPF? If so what I'd like to do is get to those WPF items so we can use them in our own apps, effectively use Excel/Powerpoint as a WPF generator.