if we narrow the list down to ten then my vote is
Adele - Hometown Glory
Beyonce - Crazy In Love (Feat Jay-Z)
Britney Spears - Baby One More Time
Estelle - 1980
Gwen Stefani - What You Waiting For?
Kate Bush - Wuthering Heights
Kelis - Caught Out There
Lauryn Hill - Doo Wop (That Thing)
Lily Allen - Smile
Natalie Imbruglia - Torn