I LOVE THIS QUESTION! Ok, here we go:
5. It's All Coming Back To Me Now by Celine Dion; 4. I Want You Back by The Jackson 5; 3. Silver Springs by Fleetwood Mac; 2. For a Pessimist, I'm Pretty Optimistic by Paramore; 1. I Won't Say (I'm in Love) from Hercules soundtrack.

Also, a bonus duet: It Wasn't Me by Shaggy and Rik Rok. Classic.