This is a hard one, tons of great music out there, and if i had to choose only one of them, then that song is Stair way to hip-hop heaven. https://www.youtube.com/watch?v=p_NnAjtUsdY and i choose that one because it have it all, a nice guitar, great drop, classic song, just all...

And my favourite singer is a hard too, you can think some one is a good singer from his voice or from his songs, so, for voice is Alicia Keys, damn, that girl make love with her voice https://www.youtube.com/watch?v=Urdlvw0SSEc and for songs would be some one in Spanish like Jorge Negrete