I cancelled on the 9th of June (service would have ended on 10th August), had 30% discount offers on the website every time I checked until yesterday when it had gone up to 50%. Inadvertently I accepted that 50% offer (there's no price breakdown to tell you what you'll be paying before you confirm) but I'll talk to them today either via live chat or phone to ensure it's a 50% discount on my entire bill. If so, I'll probably live with that, seems reasonable and doubt I'll get anything better considering it's just the basic TV package with HD.
I cancelled via live chat. Spoke to a fairly friendly person on there who wanted the usual info about how I use Sky, what I like to watch, whether changing my package would bring the price down, whether I wanted broadband and phone. The final offer was poor so I politely declined and went forward with the cancellation. They'll tell you that's the best offer available to you but it's clearly not, so don't be swayed.
I live on my own so using another name as a new customer isn't really a viable option that I'd be comfortable with, and as appealing as new kit is, I'd lose my current recordings, series links etc so it's just not worth the hassle.