Now TV have published a help guide to the boost. It appears only two Sky Sports channels are 1080/50. Sky Sports Main Event and Sky Sports Premier League. You also get three simultaneous connections,
Fox is staying at 720p and Gold in SD. As I speak, SyFy is still in SD, although that is going FHD.
Presumably most of the content on the channels that show drama is 25p (or 23.976p sped up to 25p) - so those remaining 25p makes sense. Sky News would benefit from 50p, as would any channels carrying entertainment shows shot 50Hz interlaced.
Gold would be nice in 50p when it is showing stuff shot interlaced in studio - such as sit coms.
I've seen Gold on Sky in FHD and the SD content does benefit from the upscaling. Incidentally the Gold commissions including The Cockfields is still 720p only on NOW TV VOD despite being filmed in 1080i.
From what I've seen, most if not all Sky Cinema VOD is now 1080p/50fps, live is 1080p/25fps. I've got a day Sky Sports Pass which I'll use at the weekend to test the 50fps on Main Event/Premier League.
The main benefit of going FHD has been for me personally on Nat Geo Wild. The wildlife programmes really do look much better.
So it looks like the SD only live channels are the Viacom kids channels, Comedy Central and Gold. Fox stays at 720p. MTV which is a Viacom channel has gone FHD.