Last night, the cool crowd was out in force at Nylon's party to celebrate the launch of their Young Hollywood issue. Everyone who's anyone showed up to share the spotlight and a turn on the red carpet. There was no shortage of young starlets in skin-baring dresses wearing down 'dos (as opposed to the awesome up 'dos we've been seeing 'round town). Whitney Port went down the middle with super-straight and super-shiny. Ashley Tisdale preferred tousled waves. Kristin Cavallari smoothed the front to let her loose curls fall in the back. And Ashley Greene turned up the volume on her long layers. Who do you think had the hottest par-tay hair?