Composite Video Inputs: A video input characterized by a yellow-tipped RCA jack that carries a video signal from source to source. A composite is video-only, so it requires a separate audio connection to hear sound.
S-Video: A video input that is slightly better in quality than composite. It requires a separate audio connection to hear sound.
Stereo Audio: Input and outputs that will allow connection with a RCA red and white stereo cable. Stereo connections are associated with composite, DVI, and S-Video.
DVI: A type of all-digital connection between your television and another source. Most people associate connection of a PC to a monitor with DVI. DVI connections are video only, and require a separate audio connection.
HDMI: An all-digital connection that significantly outperforms DVI in all areas. HDMI carries the audio signal, therefore only one cable is needed to receive video and audio.
Buying Advice: Get as many connections on a television as possible. Front and/or side inputs are a wonderful convenience you will be thankful for having. Component and DVI and/or HDMI are pretty much must-haves.
HDCP: A copy protection technology associated with DVI and HDMI. It eliminates the unauthorized reproduction of programs encrypted with HDCP, and distorts the signal on televisions without it. While the fate of HDCP is uncertain at this time, it is recommended that you purchase a plasma with it in case it becomes a standard for all broadcasts.
Buying Advice: I think HDCP is a dangerous technology. Anything that can prohibit your ability to record or watch a program goes beyond whatever good faith there is in watching television. But, it might become a standard in the next few years, so it is a good idea to have that option on a television just in case.
Contrast Ratio: A measurement between the lightest white and darkest black. This is where televisions earn their picture quality by displaying true blacks and sharper colors. In comparison, a contrast ratio of 1200:1 would be better than 200:1.
Comb Filter: Another way televisions display better pictures, and all we need to know is that it helps improve the overall resolution. In case you want an official word from an electronics superstore - Best Buy.com says, “Comb filters come in five flavors (in ascending order of quality): normal (glass), CCD (2-line), 2-line digital, 3-line digital and 3D Y/C comb filters. (Manufacturers who choose one of the latter types are signaling their intention to build a better set).“
Buying Advice: While you can't ignore the numbers, try to watch the television and make a decision based on what your eyes see versus solely on the specs. With a lot of added technology hidden beneath the surface, televisions are almost like cars in terms of performance.
Burn In: When a static image leaves a mark on the screen, like a station logo on the bottom of the screen remaining on screen when not on that channel. Burn in takes sometime to set in, but it does affect plasma displays.
Ghosting: A type of image defect that is associated with movement. The screen appears as though a moving image is being shadowed ever-so-slightly by itself. Ghosting can also appear like burn-in, where an image remains on screen temporarily after the channel has been changed.
Buying Advice: You can't ignore burn in, but it's such an extreme defect that most people will never have a problem with it. As for ghosting, the screen should refresh itself over time (within minutes) if ever leaving a mark on the screen.
Energy Star: A rating of electrical consumption so you will know which set is efficient and which is an energy hound.
Buying Advice: Pay attention to Energy Star ratings because electricity is part of the long-term cost of owning a television. While the electricity used by a TV might not send you to the poor house, a wise purchase could save you enough money to go out on the town for a night.