We always say that less thermal compound is better than more, and the results of these tests confirm it. The best results we got were with a small (and a tiny) amount of thermal compound over our CPU. It seems to be irrelevant that the thermal compound covers the entire CPU surface, since most of the heat is produced at the middle of the processor heatspreader. In addition, it is a well-known fact that a CPU heatspreader is a little concave rather than really flat.
The quantity of thermal compound seems to be the key variable that defines a good application. A drop about the size of a grain of rice is the best quantity, while a drop about the size of a bean is too much paste. More than that can only make a mess around your processor.
Please keep in mind that these results apply to the hardware we are using, and a different CPU, cooler, or thermal compound can behave differently.
Answering the question made on this article title: Putting a small drop of thermal compound at the center of the CPU is the best way to apply thermal compound.