Which way do I install a grounded three hole wall receptical? Two slots on top and ground hole on bottom (little face) or Ground hole on top and two slots below (christmas tree)?
Does it matter? I've noticed most recepticals have writing or numbers which are read right side up when the (little Face) method is used. Is there a standard?

It doesn't make any difference but plugs with sharp right angle turns usually have the round prong down. My current home all of the outlets were installed horizontally, don't know why, don't care either.

There is an urban legend that code requires them to be turned up. I occasionally an in the building of a large electrical contractor-they wire up big factories. All their outlets are ground up.

There is no standard or typical any longer, mount them as you see fit. The reason they use to be mounted "upside down" with the ground hole at the top is the code use to several years ago require that in all medical facilities the ground be at the top, in the event the plug fell out a bit, and if a medical tool such as a needle or a scalpel fell onto the outlet, the tool would hit the ground first. Other wise if mounted with the ground down, the tool would short out the hot and neutral, and anesthesia was very flammable and sparks in an operating room were not wanted.

As most hospitals were wired by large union contractors, many practices performed by large contractors were adopted as a standard in the trade.

This was only required in medical facilities, but did get carried over to homes and businesses.

Evidently this is no longer a problem, so the code stopped requiring the ground to be mounted up several years ago.