Technically, MS had that setup in Windows Media something or other first, years before the PS3 came out. So, technically, PS3's menu system looks like Window's Media menu system. I'd have to find the link but a bunch of people were discussing it on one of the tech blogs I frequent.
Anyway, I have played with a couple of Windows Phone 7 devices and dislike that UI for a phone. However, it looks great for the XBox menu, I look forward to this update.