Heres the racket that Maria Sharapova uses. It is the Head Youtek IG Instinct MP and weights 300g and comes with a 100 sq inch head. It has a very solid feel and is comfortable when hitting groundies. The open string pattern enables easy spin generation for those of us with medium-long swings. It offers plenty of power in the service department and volleys are crisp and deadly.
Tomas Berdych also uses the same racket. Any fast swinging base liners or net rushing doubles players, this is a racket to be reckoned with.