Home automation and remote control, as envisioned in the 1980-90s, never really took off. I think part of the problem is that automation is less convenient than the alternative. It really is not adaptable to a family oriented living unit. Big companies such as GE and IBM got into the business and out of it relatively quickly. And a bunch of smaller companies tired to join in as well. I really never needed a PC to control my refrigerator.
I do believe I purchased the Regulator modules from DAK. I never had the Regulator timer. I still have two telephone interface units that are looking for a purpose in my life. I suppose if I had a cabin in the woods somewhere (with a phone line, of course), they might be useful.
For the gas-fired furnace, indeed I did use the X10 thermostat controller. (I still have it.) It took a bit of tweaking to get the settings just right. But it worked fine for me in the heating and cooling seasons. I suppose I could have just as easily purchased a mechanical timer set back thermostat that were available. (Now they are electronic.)
For me, the primary advantage of the X10 system is multiple location remote control, rather than automation. If the lawn irrigation system is on, and I need to let the dog out, I can turn it off at the back door or front door, or garage, or even bedroom. Secondary for me, is light dimming, scene setting. Thirdly for me are occupancy sensor light controls.
By the way, after leaving the TV on downstairs for the nth time, I hooked up the X10 IR remote transmitter. Now if I can turn it off (and on) from the bedroom upstairs.
The best home automation is still, and will forever be, a full-time maid, butler and chauffeur. Sigh. . .