Roger Federer is currently using red,white,and black racket. He has been using it since the Australian Open 2007, and is called the Wilson K-Factor 90. Earlier, he was using the red and white one and it was called the Wilson Ncode.
Djokovic uses the Wilson nBlade, the balck white and gold racket. Hewitt uses the Yones Rds 001, the yellow colored racket.
All these rackets are significantly heavier than the team rackets. They are less powerful but control oriented.