usually in the garage, sometimes in the driveway. Right now in the summer it really doesn't matter either way, but in winter when we were dipping below freezing at night it made a huge difference! Left outside, my batteries would start the day at 30Degrees F, and sag tremendously under load. In the garage (not heated, but protected from the direct elements) the cells were closer to 45-50 degrees F, and acted better.
I have no battery heating.
The biggest issue I have with leaving it in the driveway is that my charger has a rather noisy fan, and I worry about annoying the neighbors.