there are 3 boxes from Comcast:

standard Def box - no extra charge comes with price plan above basic cable

HD capable box - replaces the box above and does everything it does plus received HD channels and is 11 dollars a mnth extra which includes the box rental fee so thats 11 dollars a month on top of your normal cable bill and oyu get the box with it

HD DVR capable box - again does everything the above boxes do but 15 dollars a month on top of your standard cable bill



both HD and HD DVR boxes have these options:

480i
480P
720i
720P
1080i



no 1080P yet with cable only via Dish HD boxes


almost every 720p HDTV out there can and will read 1080i even though its 720p native so no need to worry about that. if you purchase a 720p tv you will have no problems receiving 1080i HD channels OTA over the air or via cable box as long as you have the proper box