1. DVI and HDMI are exactly the same as one another, as far as Video signals are concerned.
2. That’s why a DVI source can be connected to an HDMI monitor, or vice versa, with a DVI/HDMI cable, with no intervening converter box.
3. HDMI carries audio as well as video, and uses a different type of connector.
4. S-Video carries standard definition video as an analog signal (like Component Video), but does not carry audio on the same cable (like DVI).
5. If S-Video and Composite Video are both available, then use S-Video as the first choice.
6. Difference in picture quality is dependent on the source device (DVD player etc.) and display type (Analog TV, LCD TV etc.) and not on the connector type used.
7. Analog component video is an extremely robust signal type; you can typically run analog component, without any need for boosters, relays or other special equipment, up to 200 feet without any signal quality issues at all.
8. High quality cables for both S-Video and Composite Video can traverse long distances.
9. DVI and HDMI, unfortunately, are not so robust. We have found well-made DVI cables to be quite reliable up to 50 feet, but HDMI cable, with its smaller profile is more of a puzzle. Keep it to 20ft max. as a rule of thumb.

Ref:

• http://forum.ecoustics.com/bbs/messages/34579/122868.html
• http://en.wikipedia.org/wiki/S-Video
• http://www.extron.com/company/article.aspx?id=svideoprimer