This is "Home Automation" and when properly designed and installed a system will be a fusion of both examples - i.e. a simple uniform control interface that allows the user to operate many systems and devices, but those systems and devices are able to monitor their surroundings, and react appropriately to their changes to meet user requirements.
The most efficient Home Automation systems need not be horribly complex, but they are always best done by an expert, who can specify, plan, install and configure. The system will then work, with minimal fuss, meaning maximum energy efficiency, maximum ease of use, and importantly maximum security.
Our experience has lead us to focus on a few carefully selected products that can be part of or all of the elements required to achieve "Home Automation".