My Denon runs warm, but not hot. It's in a wood cabinet my wife and I built. There's only about half an inch of space on each side, 5 in back, and 4 up top. Even when running a 7.1 set-up it will only get about 50 degrees Celsius inside the cabinet, but I installed a fan I bought off eBay to make sure there was some air movement around the thing. I was told by a respectable dealer that only if the AVR shut off on it's own or was too hot to touch that it was running to hot.

"Not throwing my hands up or my dress above my ears don't mean I ain't awestruck." Al Swearengen