Ben Folds. Though technically he's just one person. If it must be a group, I'll go with Ben Folds Five.

The two major reasons why I like him (other than the fact that he's awesome) are:

1. He plays piano
2. He's funny

I play piano myself, which is part of the reason I like him so much.

The Beatles.They became famous very quickly,and then could change their music style without the harassment from the record companies on what they should play.In fact they opened up their own record company,so they had total freedom on their creativity.So they changed rock music in the 1960's and 1970's.
Secondly it would be Neil Young,for he only made the records he wanted and refused to buy into the music system with record companies trying to force musicians to make records when they are not creatively ready.He has gained much respect among his peers.