What DS games do you consider to make the best use of the dual screens?

In Lost Magic, you need to memorize it in mind in order to cast it correctly. But, this will take accuracy.

Mario Kart DS, because of the map of where you have gone now, it is easy to take track of your whereabout while at race.

All the action takes place on top screen while bottom shows your manga panels. Click whichever you might not have hot linked to activate special moves and what not.