Blake Lively

(Serena) is played by Blake Lively, who clearly should be a young male porn star but is not.

—From Lucy Mangan's review of Gossip Girl in The Guardian on its British premiere.

Actress born on August 25, 1987 and famous for The Sisterhood of the Traveling Pants, The Town, being a fashion darling, hanging around with Leonardo Di Caprio and Ryan Reynolds, having legs for miles and, of course, Gossip Girl. Not so much for Accepted.

The Sisterhood of the Traveling Pants
Accepted
Simon Says - not to be confused with the one with Dennis Rodman, but a horror flick starring Crispin Glover and produced by her father. ^[1]
Gossip Girl
Elvis and Anabelle
The Sisterhood Of The Traveling Pants 2
New York, I Love You
The Private Lives Of Pippa Lee
The Town
Green Lantern
Hick
Savages

Absolute Cleavage
Billing Displacement: See Simon Says above.
Beauty Mark: It's on the left of her face, a la Cindy Crawford but smaller and nearer the nose.
Distracted By the Sexy: Her detractors accuse her male fans of being thus.
The Fashionista: Lagerfeld, Chanel, Wintour...
Everyone Loves Blondes
Gender Blender Name: See page heading quote.
Life Imitates Art: Alhough Blair (Leighton Meester) arguably became the breakout character of Gossip Girl, Serena's tendency to upstage Blair eventually crossed over into the actresses's real lives. (And their box office returns - Green Lantern certainly wasn't a blockbuster, but it still did better than Monte Carlo. And The Roommate. And Country Strong. And...)
Ms. Fanservice: And not just on screen - we're talking about a woman who attended the premiere of Sherlock Holmes showing a lot of skin. In December. In New York City. Now that's dedication.
Romance On the Set
She's Got Legs: And how!
She Really Can Act: Blake got more than a few positive reviews for her turn in The Town.
Star Making Role: Serena van der Woodsen.
Statuesque Stunner

↑ Fun fact - Blake is billed as the second lead but only appears in the last five minutes of the film, and plays a victim to be to boot.