The Xbox 360 has used multiple different type of heatsinks for cooling the processors.
Xbox 360 (Original)
The Original Xbox 360 used 2 heatsinks: one for the CPU, and one for the GPU. There were also 2 different versions of each heatsink.
Used on the Xenon, Zephyr, and Elpis motherboards. It was also used on very early versions of the Falcon motherboard.
Used on the Falcon, Jasper, and Tonasket motherboards.
Low Profile GPU
Used on early/mid Xenon motherboards, Zephyr_A motherboards, and returned on the Tonasket motherboard.
Used on late Xenon, Zephyr_B/C, Elpis, Falcon, and Jasper motherboards.
Xbox 360 S and Xbox 360 E
The Xbox 360 S and Xbox 360 E use a single heatsink for the CGPU. There were 2 versions of the heatsink. Both versions have a fan mounted on them.
Heatsink with a fan mounted on top
Used on the Trinity motherboard. This heatsink was only used for a brief time.
Used on the Trinity, Corona, Waitsburg, and Stingray motherboards. It was also used on Winchester with slightly shortened pegs on the bottom, as Winchester removed the IHS.