I guess blackpool is okay, since you have pepsi max big one and ice blast. But personally I would choose Alton Towers, although it's a big park, there isn't too much in it, but they have some nice rides, e.g. : Oblivion, Nemesis and a few others.
Thorpe Park would definetly by my main choice though, it's a small park packed with a load of rides. I'm pretty sure I can safely say every thrill ride there is actually good.