The Ideal System Architecture

There is no point in trying to define an architecture that will be suitable for all systems.  The architecture of each system should reflect its particular functional and non-functional requirements, and the constraints that affect its development.  The technologies available also change every few months, so any ideal architecture would quickly become out of date.

However, if designing a state-of-the-art, web-based business application in 2009, the layers would probably look something like this: