I have mine horizontal. It made indeed a lot of noise with the disc loading, when the PS3 was standing vertically. The ventilation openings have more than 6 inches of space for cooling, so I don't see any problem there.

And blue means the coolest spot, red the hottest. Shees where is this thread going to... hot... cool, horizontal position, vertical position... Anyway, Kber81 is right, you only have to feel your PS3 to find it out yourself. The parts that show green / yellow / red are the ones which show the most warmth. I've noticed this with my PS3, and thats the bottom and the left side when standing up, once you're standing in front of the PS3.

Screw the console wars BS, this is the PS3 position war..this is epic.

(Horizontal for me, seems quieter?? probably just due to acoustics not mechanics...and my frame rate is up to 120fps ;) )

horizontal.

My PS3 is horizontal right now. It looks attractive that way and it so it also doesn't tilt over.

The Wii has a stand to keep it up straight. I have my 360 horizontal.

I wonder how the temperatures of the PS3 compare to that of the X360? X360 horizontal and vertical temperatures?

Having had looked at the analysis of the graphs on the horizontal PS3 temperatures versus the vertical temperatures of the PS3. Horizontal PS3 remains cooler. Hot air rises in the vertical PS3, resulting in higher temperatures of the PS3.

I like mine laying down.  It still seems weird to me to have a console standing up.