The Nest
I wanted a Nest bad when they first came out, but I waited too long to order. When they recently became available again I ordered right away and a few days later we replaced our old "smart" thermostat with the shiny new Nest.
Imagine the change you went through when going from a dumb flip phone to the iPhone or other smart phone. That's what it's like with the Nest. It learns your schedule. It's very easy to change the temp whenever you need to, and you can do this directly, or via the web page, iPhone, or the iPad, and you can do all this remotely. Want to turn the temp up or down while an hour from the house? You can.
It's just works. Sound familiar? If you didn't know better you would think it was from Apple.