Well, technically, it's illegal (in Illinois) to coast or stop with your car in neutral, so there's that.

On a normal stop, I typically don't do either. I just apply the brakes, with the car in whatever gear it's in, and push in the clutch right at the moment where it's necessary. I think, technically speaking, that is the "right" way to do it.

Coming to a quick stop, or just having a good time, I drop to a low enough gear and pop the clutch out so it locks up the back tires for a second. Not as easy to do in the car as it is on my bike.