re: SD vs HD, is dependent upon who you ask. The CEA, which represents the TV makers, says that anything with at least 720 lines is HDTV, thus enabling 1024x768 to be called HDTV. ATSC, which develops broadcast standards, says that HDTV should be 720 or 1080 lines at 16:9 aspect ratio, which implies 1280x720 or 1920x1080.

I think most TVs now are 1280x720 or 1366x768.