I use GarshneBlanker on my A1200 and A600. It has heaps of modules to choose from, a nice GUI to configure the settings with, and it works smoothly without crashing other applications like some blankers can (although there are some unstable third-party blanker modules which are best left out).
Yes, I've been using this for years, too. One of my favorites draws an elaborate maze with start and end points. Then the Amiga solves the maze. It's very cool in high res.
I also enjoyed the Matrix savers, especially when the movie had just been released.
I'll have to try Madhouse.