Carlton Bale has an interesting blog post on his investigations into choosing an Advanced Thermostat for his home. Well worth a read of you are considering automating your heating/ventilation system...
"Let's face it, the thermostat that is installed by default in most dwellings is pretty basic. If you have a digital display that's the "upgraded" version; and all it does is replicate the functionality of the old rudimentary mercury switch / rotary knob designs. An advanced thermostat with scheduling features can save quite a bit on your energy bill, but can also be an interesting gadget to occupy your time. Since my energy company is offering a rebate for anyone who upgrades to a scheduling thermostat, I decided to pull the trigger...