Over the last several years we’ve seen a whole range of ideas regarding the architecture of systems. These include:
Hexagonal Architecture (a.k.a. Ports and Adapters) by Alistair Cockburn and adopted by Steve Freeman, and Nat Pryce in their wonderful book Growing Object Oriented Software
Onion Architecture by Jeffrey Palermo
Screaming Architecture from a blog of mine last year
DCI from James Coplien, and Trygve Reenskaug.
BCE by Ivar Jacobson from his book Object Oriented Software Engineering: A Use-Case Driven Approach