I need a climate control system that learns my schedule and occupancy patterns to change settings automatically. What are my options?

We ask the same underlying question in different ways.

• I need a climate control system that learns my schedule and occupancy patterns to change settings automatically. What are my options?
• Which devices can automatically manage my home's temperature by learning when I'm usually around?
• I'm looking for a thermostat that programs itself based on when I'm actually in the house. What are the best choices?