indeed a Media Center, largely on account of having the
Windows Media Center Edition
operating system. Intel describes it as "a new platform designed for the enjoyment of digital entertainment." What that means is that you should feel comfortable that if you purchase a PC with a Viiv sticker on it, it'll be optimized for multimedia use--although people's definition of multimedia use may vary widely. Viiv is also supposed to support things such as 5.1 or 7.1 audio and Intel's Quick Resume instant on/off technology.
Since Viiv is an Intel platform, it makes sense that an Intel CPU is required. Systems must have a dual-core Intel Pentium D or Pentium Extreme Edition processor. Laptops must have a new Intel Core Duo CPU. If you're interested in delving down deeper, the chipsets supported by Viiv are the new Intel 945/955/975 Express chipset family. An Intel Pro/1000 PM or Intel Pro/100 VE/VM network connection is also required. Don't take my word for it, the full requirements are posted on
Intel's site.
Can you have a satisfactory Media Center experience without Viiv? Of course you can. While it's nice to have some easy-to-understand branding on a system, you should base your Media Center purchase on the specs, the components, and the price point you're looking for. That might lead you to a Viiv PC, but then again, it might not.