SANTA MONICA, Calif., Jan. 16, 2000 -- Tired of Oscar-worthy dramas? In the mood for (hey!) a teen flick? Your time is here (again). "Down to You," a Generation Y romance starring Freddie Prinze Jr. and Julia Stiles, leads the pack of new releases this week, presumably to the delight of the nation's mall rats. Elsewhere, a host of critically acclaimed (or in teenspeak: boring and long) films previously in limited engagements will add screens. That list includes: "Angela's Ashes," "A Map of the World" and "Titus". Here's a complete list of films opening this week: FRIDAY: "Angela's Ashes" (Paramount) -- Adapted from Frank McCourt's Pulitzer Prize-winning memoir, this film documents the author's childhood in Ireland during the 1930s and '40s. Emily Watson ("Hilary & Jackie") and Robert Carlyle ("Trainspotting") co-star as Frank's working-class parent