Well when you stand it up vertically, a vent is being covered and the disc seems like it can slip off the tray. Horizontal seems like the logical way to go.

If the X360 warm on the bottom and cool on top it's because the heat is more trapped on the bottom  than the top. The same goes with a laptop.

D'oh!

whoever said that cool air rises and that hot air falls is a tard. In a chemical sense the hotter air molecules moves faster and are less dense therefore they rise whereas cooler denser air falls. What grade are you in?

have you ever felt how hot under the xbox is when its horizontal? i keep mine vertical to help disapate heat.

Horizontally, like old school :)

Hey dude that was uncalled for.

XD what? Heat rises my friend. 

yeah heat rises trashy is correct

as for how to place it its up to u on which way looks better the system was design to be put either way

vertical would make the system run the coolest though if u have ur system laying flat horizontally put ur hand underneath the system ull see its hot and the heat has no where to go less surface area is exposed

having it ver will make it act like a radiator making more surface area of the system exposed to the air

LOL. poor Garnett is being treated appallingly. don't worry buddy, you had me questioning one of those lessons i learned when i was like 7. until i thought about hot air balloons.

you tried, that's all that matters.