Young Hollywood was out in full force for last night's Myspace launch event. The style-setting crowd brought out their best party looks — each with her own unique twist to celebrate at the El Rey Theatre in Los Angeles. Olivia Wilde mixed a few major trends, adding a leather jacket to printed denim, and finished the whole look with a pop of red on her heels. Jamie Chung perfected cool-girl eventwear in a printed miniskirt, breezy tank, and statement jewels, while Dianna Agron was the most ladylike of the bunch in a floral-print A-line skirt, white button-up, and pointed-toe heels.As for the rest, Miley Cyrus and Amy Smart turned out two distinct takes on denim. Miley furthered her fashion transformation with an edgier ensemble that consisted of baggy boyfriend jeans, a slick crop top and jacket, white-hot pumps, and a platinum coif. Amy played it a little more casual in a pair of skinny-fit jeans and a Western-style button-down with suede booties to finish it off. Now that you've gotten the outfit breakdowns, it's time to cast your vote. Who was last night's best dressed?