By any modern measure of musical popularity -- YouTube views, radio airplay, ring-tone ubiquity -- the single "Best I Ever Had" by Toronto rapper Drake is not only a hit, it's arguably 2009's "Song of the Summer." Since debuting on iTunes last month, the hip-hop lust track has sold 600,000 digital downloads and topped three separate pop charts. Even if you can't summon to mind its rap-sung vocals or brassy syncopated beat, you've probably heard "Best I Ever Had" blaring out of a convertible somewhere.
