I was just alerted to this whitepaper that has a very good discussion about using
WF versus when to use BizTalk.

For those of you that are previous readers of my blog I’m an avid fan of WF and BTS
working together to solve solutions rather than a common message voiced by at times
MS – “you *must* choose one or the other”. I did a webcast on
this years ago.

Kent Brown the author does a very good job – well done!!!

BizTalk Server 2006
or WF? Choosing the Right Workflow Tool for Your Project