Good Audition Songs (that are not overdone)?

Hey people! I'm 15 (soon to turn 16) female. I have a good range. I sing Soprano in my school choir but I have also sung Alto and tenor to give you a good idea. I just need a few good songs because I'm planning to enter into the audition circuit. I plan on auditioning for BIG RIVER at the end of this month for starters. So if you could give me some songs that will get me noticed and make me a good choice. Thanks for all the help!