With a 720 on a GMATPrep test, you're pretty close to being ready. I would review any weak areas and do extra practice questions on those, then do the other GMATPrep test. Or do the free test on http://www.princetonreview.com
and then save your second GMATPrep for two days before the exam.
The night before the exam, no prep....just relax. Watch a silly movie or hang with friends, but no partying.