girl duets?

Question:

Guy/girl duets?

I just posted, like a day ago, about solos and group songs for a competition.
and I got amazing feedback (I now have to choose between like, 8 songs for a solo to do....lol)
But I was wondering, are there any great guy/girl duets out there that I could do at this thing?
Thanks for all your guys' help so far!

Best Answer - Chosen by Asker: "follow your heart" from Urinetown is sort of wonderful. Let us know what you decide on altogether at the end!