Laventura is right - the 1070 will add OSD information to a 480i signal, but not a 480p or higher signal.

If your satellite receiver offers 720p and 1080i and your TV accepts them, then you have an HDTV and presumably have access to at least some HD channels via satellite. In that case, using anything other than 720p or 1080i is probably unwise - you'd be giving up HDTV to get OSD info from the 1070. Whether 720p or 1080i is better depends on your TV and its native resolution.