SharePoint 2010 includes one major new thing: Visio Services. With these services you will be able to create great visio diagrams, hook them up to live and static data, and then publish them to your SharePoint site. The diarams will be rendered in the brwoser, and therefore now need for a local Visio client viewer.
Several demos at the conference have shown some great capabilities of these Visio Services. They will be a part of the Enterprise license, and I think you all must upgrade soon to get the complete "package": Excel Services, Forms Services, Business Connectivity Services (the "old" BDC) and now also Visio Services.
The following picure illustrates what can be done (illustration copied from Visio blog on Msdn)
More will come.