I love comparing Ariel with Caliban. They have similar goals (getting their freedom), but they go about their goals in very different ways. Ariel works with Prospero, does his best at his job, and tries to win his freedom without cheating his master. This loyalty comes from the fact that Prospero freed him from a tree, in which he had been trapped by the witch who once inhabited the island. Caliban feels no loyalty to Prospero, and so he works against him, plotting his death.
The song I Want To Break Free, by Queen, makes me think of Caliban and Ariel, because it shows their desires.
http://www.youtube.com/watch?v=QgQaa_B6ATI
-Jennifer
onlyfriendsstealyourbooks 
I also really like the idea of comparing Ariel and Caliban, because there goals of freedom also bring up the theme of control, along with the difference between slave and master. Ariel is originally treated with respect and cared for by Prospero when he frees him from the tree. Not only does this give Ariel a glimpse of hope for further freedom, but he then is in a respectful relationship with Prospero. This differs from Caliban, who is always treated as a slave to Prospero. This lack of respect causes Caliban to hate and plot against Prospero.
–Steph