Good evening.
You have BBC-HD and ITV-HD as a red button service. Word on the street is that Channel 4's ill-advised exclusivity deal with Sky will expire by December, allowing C4-HD to join Freesat by the end of the year. There is some suggestion that Luxe-HD may also join, however I'm not sure how much of a selling point that is.
Freesat-HD is about the future of FTA broadcasting. Almost none of the HD channels currently on Sky are going to feature on it as they are all HD versions of channels that were already subscription-only. But there will come a point where all the main pubilc service channels will be broadcasting entirely, or mostly, in HD (i.e. BBC1 in HD, BBC2 in HD, rather than a separate HD channel). Freeview isn't going to be able to cope with this; only Freesat has the bandwidth.