There is a thread in the main TV forum about "possible" HD additions in '09. I don't think that they will add anything extra to the channel line up due to VM's Xmas IT upgrade blackout.
Expected might be the Sky HD packs now that VM have sorted out the SD channels. ITV HD, 4 HD, SKY 1 HD, FX HD and the Discovery HD stuff added too...
(well i can dream... lol)
as well as BBC HD you also have the on demand stuff that is really good if you are into nature and stuff...
- one other thing was Setanta Sports HD - That might be on a premium though. (Setanta HD cameras were at the FA cup 2nd round match with Barrow v Brentford on the friday - there was a massive HD van parked at the end of the pitch so i am guessing that they just transmit in SD and not in HD due to cost.)