I can't think of anything better than Maya v/s Max and there's lots of info on the web on the subject. Should make the essay easier to complete.

Other topics:
1. Modeling with polygons v/s nurbs.
2. Paying for Maya or Max (full versions) v/s getting it for free (pirating it). And, using it for commercial purposes. Many people don't think there's anything wrong with pirating, even though it's illegal. Should make for a good debate.

good luck with the essay!

Edit: Sorry Jr. Who, didn't see your post until after mine was updated. Sounds like we were thinking the same thing though.