If you're looking for a multimedia computer but not sure where to start, be sure to check out this NYTimes.com article that states:

Most multimedia machines come with powerful Pentium or Athlon processors, the latest graphics cards, FM radio and television tuners (sometimes more than one, so users can watch one channel while recording another), DVD recorders and enough memory and hard-drive space to store and play back hours of high-quality programming. Many also incorporate the Microsoft Windows XP Media Center Edition operating system, which adds specialized multimedia features to Windows XP.

Because the entertainment PC's are designed for living rooms, they come with wireless keyboards, mice and hand-held remotes for controlling functions far from the computer. Nearly every major computer maker is now producing entertainment PC's as laptops and desktops, and even as horizontally designed machines that resemble stereo components.

Read With a PC's Power, That's Entertainment