EngadgetHD ran a poll this weekend on how many HD channels readers have at home. Keeping in mind that the EngadgetHD audience is geekier than your average room full of people, I was surprised by the numbers as of Sunday night. More than half of the respondents acknowledged having fewer than 20 HD channels. That means there’s an awful lot of room for growth, and a lot more bandwidth needed to broadcast the volumes of HD that consumers are starting to demand. A good reason for switched digital video.