I would recommend Soulja Boy Tell 'em - Crank That / Chamillionaire - Ridin' for this achievement.
Even on Expert, the speed is still pretty slow, and the scratches are as simple as it gets. It's pretty heavy on taps, so the "Tapmaster" deck (or whatever it's called) is a good bet for a great score. It's also pretty easy to get rewinds, and remember to use them. They can greatly boost your score.
I am no master at this game (I usually play on medium), and I maxed out the star meter, i.e way past 5 stars, on my first try, very easily.
Then it's just a case of repeating at each difficulty level.