http://www.windowsworkflow.net. WWF will offer a unified way to create both system and human-based workflow (There goes Biztalk HWS ...). Products such as Office12, WSS V3, Biztalk and MBS will make use of this new architecture. I can't wait to get my hands on that one.
The demo with WSS V3 was especially interesting:
Some interesting links:
I will write some more postings about enhancements to SharePoint in the coming hours... but this definitely was worth it.