I guess any drop tower, but I love Giant Drop at Dreamworld. I felt REALLY unsafe and frightened at the top, and it felt like the tower was just going to fall over, and then you just drop. It takes a few moments to realise you have dropped, but then the freefalling feeling kicks in and its great! Also, I know this sounds weird but when I went on Lethal Weapon (SLC), it was my first coaster in years, and I wasn't expecting the drop to feel like that, very forceful.