Girls Aloud.
Two reasons why they are the best:
1) They are fucking goreous (apart from the Ginger one)
2) They don't sing about girls being independant, or being free, or "not needing men" like every other woman/girl band in the world has. They actually sing about being the total opposite of that. *
But being the best pop group doesn't really say much.
That's like being called the best piece of dog ****.
Edit: * Not that there is anything wrong with women being strong and independant, etc. I just don't wanna hear another fucking song on the subject.