Entertainment Center Cooling?

skubalon asks: "I have a decent bit of audio equipment for my home theatre. All of it is housed within a wooden entertainment center with a glass door. This doesn't do much for keeping my system cool. I have tested and found that the ambient temperature in the cabinet does not go higher than 100F (37.7C). I know that my receiver has a thermal shutoff, but is this safe? What have other readers done about cooling home audio equipment?"