This is surprising. I didn't know that the XBox 360 case was designed by a Japanese design lab.
The machine was designed by Hers Experimental design lab. in Japan, lead by Mr. Chiaki Murata and Astro Studio in the US, under the direction of Microsoft's Jonathan Hayes. From the start of the project to its final design, Microsoft constantly tested the design with users all over the world. With this technique, they have been able to create something that appeals not only to the Japanese consumer, but to people all across the globe. The simple, curved design contrasts starkly with the major processing power inside the machine, and gives a refined look that can be coordinated with any interior. Their words, not ours.