I had a similar problem with Cablevision when the guy came over to swap a HD-ready box (Scientific Atlanta) for the regular digital one. He did not properly go through the setup to allow 1080i output (via an undocumented method that required the right tech support). For an 80" wide screen, the 1080i signal is noticeably better than 480i from the other channels (although there is 480i variance), plus the wide screen image to boot. Unfortunately, the Rangers didn't make the playoffs
(MSG and FSNY are in HD; guess I'll have to watch Devils and Islanders).
Doug