@kettch:Part of my "leaving for vacation" routine is to go around and unplug everything, turn the thermostat off in the summer or at 50 in the winter, and to turn the water heater to "vacation" mode (basically just keeps it from freezing). So to answer your first question, no. :)
For the second question, waiting an hour or two for the house to get comfortable again is fine with me. In winter, put on a sweater. In summer, turn on a fan. Honestly though, with the curtains closed the house tends to stay under 80F inside on its own, which isn't too far from our daytime 75F setting.
NEST was mildly interesting until I realized that it works with motion detection. We almost never walk in front of the thermostat.
Would I opt for a networked thermostat if I was buying a new one? Yeah, probably. But I wouldn't replace the one I have just to get some mildly convenient features. The other home automation stuff doesn't interest me. Unlocking your door with your phone? That's just waiting to be hacked. If my sibling/neighbor needs to check on the house, I'll give him a key before I leave. My smoke detectors beep when they need a new battery (which will probably last longer if they're not connected to wifi).