I have been working with BizTalk Server since BizTalk 2000 and decided that it was about time that I started sharing my experiences with the product. I just published a whitepaper on MSDN with a lot of input from the product team.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/BTS_2004WP/html/ed17b4fc-ddc1-4a41-a134-7d11b2ea3a87.asp?_r=1
Enjoy!!