May be old news, but it is new news to me. Here is a link to the SharePoint Deployment Guide, a quick read leaves me with very good impressions of the detail provided.

Link to guide

I also wanted to share this example Logical diagram from the product team, which is GREAT.

http://blogs.msdn.com/sharepoint/archive/2007/04/09/investing-in-logical-architecture-design-samples.aspx

Enjoy!