what is the best orientation for an xbox console for best heat dissipation

I was wondering if there was any empirical evidence that placing the xbox horizontally/vertically facilitates better dissipation of heat w.r.t the other orientation? What is the best strategy (apart from not using it heavily or using external cooling) to ensure the console does not overheat

The vents on the Xbox 360 are on the sides, when it is sitting horizontally. You'll get the best airflow if you have it sitting horizontally. That being said, the heat is largely generated on the bottom of the machine, when it is horizontal. For best heat dissipation, you'll want to have it sitting horizontally, with it propped up slightly so the bottom can breathe.

Another side effect of standing it vertically is that it has a greater chance of scratching disks. You'll mitigate that by having it sit horizontally.

A system that I use is to leave it horizontal, but raised up on four small feet (anything small that you can place under the four corners will work.)

No side is butted up against a surface this way, and air can cool all sides.