So, the whitepaper has finally been published...
In summary, this covers the differences between workflow in Windows SharePoint Services (WSS) version 3 and Microsoft Office SharePoint Server (MOSS) 2007 through the use of specific scenarios. It's a pretty good read, particularly useful if you are thinking of developing on top of WSS/MOSS for sure.
For me, the most powerful use of Workflow comes through integration with InfoPath... If you want to know more and read it for yourself, you can download it directly from here