Absolutely Toyland Tours, was gutted when it was ripped out, and it was made only worse by what took its place.
I only got to walk through the back of Charlie once when I was working there, and there's still a section where the old queueline bridge over the channel still exists, so sad.
It just embodied Alton Towers magic for me, I'd have loved to have taken my own kids on it when I have them, I don't think there's any real worthy equivalent of it now.
This is closely followed by Dynamo, on its FV site... loved that ride! I did ride The Black Hole, but I wouldn't say I ever really miss it..