As every book, every evangelist would say about the current version of the product (until beta of the next version is out) MOSS 2007 is unlike anything anyone has seen before or after. It is built on .net FXs 2 and 3.5, the later for WWF&WCF I presuppose and ASP.Net 2.0.

Some of the interesting points to note

• it uses HTTPHandlers for directing to WSS code from ASP.net code rather than directly rerouting from IIS using ISAPI filters... so what? one may ask and the reply (which i am going to demand from every asp.net guru i am going to interview, hence forth) is that the asp.net context would be set and be available for http handlers  - READ THIS AGAIN
  
• uses the master page feature of asp.net 2.0 
  
• customized pages (unghosted) are stored in sql server and rendered using asp.net 2.0 virtual path feature, i.e, no more are we bound to have a physical file to be compiled and converted in to html in asp.net 2.0 and SPS leverages that
  

that is all worth while to list in the definitive guide.. i remember reading more in inside wss.. so this post would most definitively have an update