No longer a haven for the glittery club kids who spill into the streets in the wee hours of the morning, Lansdowne Street is changing its tune. (Because, frankly, those club kids aren't raving the night away quite like they used to.) First on the docket was Ken Oringer's chic taqueria, La Verdad (One Lansdowne Street, Boston, 617.351.2580), while the Quarter and Rocket (36 Lansdowne Street, Boston, 617.536.2100), formerly home to the Embassy and the Modern, have morphed from dimly lit nightspots to casual drinkeries. And while the Lyons Group won't confirm or deny plans (which we take to mean that big things are in the works), it's been reported that Avalon and Axis will be razed to make way for a 2500-seat, 35,000-square-foot concert venue.