Well, I'm not sure of your music likes but here are some I can think of off the top of my head. Halo by Beyonce. In My Head by Richy Nix. My Immortal by Evanescence. Need You Now by Lady Antebellum....
I myself am a piano player and would suggest Fur Elise. It is quite easy, but still a good song.
I do not believe there are any. However, Already Home (off their new album, Welcome to the Masquerade) has piano for the verses.
The Old Black Magic would have made an ideal theme song!
Sonata, Etude in E Minor, etc.