This week was filled with exciting announcements and new music, punctuated by Katy Perry's big news that she is pregnant, as she revealed in a gorgeous music video for her new song "Never Worn White."In addition to Perry, the Dixie Chicks announced their return and dropped the first taste of their forthcoming album with the brassy "Gaslighter"; Lady Gaga finally announced her sixth album; and Enrique Iglesias and Ricky Martin announced a joint tour.Amid the fun news, though, Nashville was