I highly recommend a block heater. I picked one up, just haven't installed it yet. The car will be up to temp within a mile (versus 2 or 3), without 10minutes of idling, using gas, and needless emission. Remember- a cold engine has few emission controls until the catalytic heats up. Might as well put that dirty exhaust to work moving the car. Also, when it is started, the fluid is already warmer- that much better for the engine overall (but minimal benefit).

Yes of course the heater uses electricity...probably from coal. But from a well-regulated power plant that can generate a single kWh more efficiently than a cold ICE can.

There are some threads back a way here and in the civic forum about block heaters and the cost to install and use them vs burning gas is idle or even just cold-engine driving with low FE. The heater does well in comparison- payback potentially within one season.