This week was all about...coming out on top. And the winners are...

Mariah Carey in a black Zac Posen gown at the "Precious" screening in Los Angeles. Previously seen on Kate Winslet, the unique cleavage cut and body-hugging shape offer a playful take on this otherwise basic halter dress.

Leighton Meester wearing a floral, brush-painted Prabal Gurung sheath at the 2009 Library Lions Benefit. The oversize flower made from the dress' material is so powerful that it manages to steal the spotlight away from Leighton's exquisite hair and makeup.

Beyonce sparkling in an Atelier Versace fishtail gown at the 2009 MTV Europe Music Awards. Out of all of the Versace gowns I've seen on the red carpet lately, this one has to be my favorite. The intricacy and intensity of this dress (complete with geometric bead detailing, allover shimmer, and a fresh take on the modern-day corset), make it hard to look away.

Eva Mendes rocking a multicolored Chris Benz dress at "The Bad Lieutenant: Port of Call New Orleans" premiere in Los Angeles. Now this is one girl who knows how to have fun. The usually conservative actress kills it in a plunging sequined bodice that proves colored glitter is not longer just for kids. She gets bonus points for choosing a dress without pockets.

Katy Perry working a nude-colored Marchesa gown at the 2009 MTV Europe Music Awards. Just when you think this fearless fashionista has lost it, she goes and finds it (and then some) in something absolutely stunning. The floral lace detailing on this gown (also present on a style worn previously by Blake Lively) is almost enough to distract the eye from the perky push-up and whimsical cross-layering of fabric throughout.

Check out more sensational celebrity styles in my Fab Five Looks of the Week lookbook.

Photos (left to right): Jason Merritt/Getty Images; Mark Von Holden/WireImage; Kevin Mazur/WireImage; Steve Granitz/WireImage; Ian Gavan/Getty Images