While I agree with much of this, I think there is a lot of value in logical (not phsyical) separation of the presentation code (templates, XSL, some PDF writing module, etc.) and the domain objects (where the actual logic of the application goes). Keeping them separate doesn't help performance or scalability, but it does help with maintenance, making it much easier to change things later on. Tangling up the SQL with the HTML-generation and the application logic makes it really hard to do general changes, like adding caching to all your database calls.