Here’s a snapshot of action in the iTunes Store on the morning of what is now (if Monday is the new Wednesday) the new Thursday. Points of interest include tangible evidence of the horse race between Dr. Dre and Luke Bryan as it plays out in terms of dueling preorders, with Luke gradually gaining ground following the weekend euphoria prompted by the Dre announcement. On the right-hand chart you’ll find a microcosm of a more long-term horse race between Columbia and Republic, which between them have locked up the entire Top 5 and 60% of the Top 10. Dang.