Speakers are nothing without a home entertainment system. The most crucial component of the entertainment system, the receiver, is responsible for taking sound data -- from a Blu-ray movie disc or a computer streaming a movie from Netflix -- and piping it out to the speakers. A good receiver supports a large number of inputs and outputs, from high-def digital HDMI and optical connectors for video and audio to analog component ports to individual speaker channels for a 7.1 setup. There are tons of elements that go into picking out the perfect receiver, so do your research before you buy anything. Online guides like Crutchfield's "Receivers: How to Choose" are great places to start.
Unfortunately, our work's not done yet -- there's more to building a home entertainment system than picking out a receiver. The receiver takes the audio and video you want to play and routes it to the proper place, but you still need a way to play those DVDs, Blu-ray discs or Web videos. A vital element of any current home theater is a Blu-ray player, which will allow you to watch 1080p HD movies with Dolby Digital surround sound audio. Another excellent addition to a home theater is a media center PC, which is a computer built expressly for storing and playing back multimedia content on a big-screen TV. Today, software like Boxee is designed to aggregate Web video content and the video stored on your own computer into an easy-to-use interface designed for large screens rather than computer monitors.