Imagine is a good song but isn't it kind of easy? I know nothing of music or vocal stuff but it seems very basic, would that hurt you in anyway?
How about this song? I'd leave out the part about child abuse though. Also that part at the very end is optional
[ame=http://www.youtube.com/watch?v=iYw8JR1N90o]YouTube - Sinead O'Connor-War[/ame]
If that's too strange than maybe the Bob Marley version!
[ame=http://www.youtube.com/watch?v=I9CG2iE2vxU]YouTube - Bob Marley - War[/ame]