If you want a free Sky+ box, I believe the standard script is to phone up and ask to cancel, and once they transfer you to Retentions, tell 'em you love Sky but you just don't have the time to watch all the stuff you want to watch. They should then offer you the 'perfect solution', for free (or at least, at a reduced price).
I would always recommend cable broadband over ADSL. Generally it's a far more stable technology and is usually faster than the ADSL speed actually available at your address (as opposed to the speed advertised in your area, which is invariably way higher).
I'd have cable broadband again in a flash if I could, but I live off-net these days so I don't have that choice.