I've never been a fan of "scratching" -- the practice of sampling beats and melodies off a manually-controlled turntable. Too often it is just this godawful skritcha-skritcha that doesn't add anything to a song. Except, well, that godawful skritcha-skritcha.
There are artists that transcend the genre, though, like Fatboy Slim (I'm not sure if he works with turntables much, but he certainly uses loops and samples) who rummage around in the old toolbox and manage to assemble something fresh and new. I was so impressed by his backing music on a Mercedes-Benz commercial that I went out of my way to find out what it was. Me praise "Praise You." Warning: Embedded video/audio.
Also these guys. I'm not sure of their name (the video is titled only Scratch masters), but they move seamlessly from jazz to Dixie to Brazilian samba to the blues, all without apparently changing records. That must be one hell of a K-Tel compilation package.
Bonus: They are (sort of) choreographed! Who says that white boys can't shuck 'n' jive like The Commodores?