Summer Sophisticates And Style Slip-Ups: Best And Worst Wednesday

Summertime is in the air and celebs are getting into the groove, wearing the latest warm weather fashions.  Reese Witherspoon shopped until she dropped at Barneys New York in Beverly Hills, showing off her superior style sense wearing a bright, geometrically patterned mini with Christian Louboutin wedges, a quilted Lanvin bag and a fab fedora.  Amy Winehouse, on the other hand, had a bit of a slip-up!

The surgically enhanced singer showed off a bit too much of her assets in a lowcut bustier top, shoving a pack of cigs into the skimpy top to make matters worse.  With a bandana tied around her head and acid-washed skinny jeans added to the mix, the bad girl was in desperate need of wardrobe Rehab!

Cameron Diaz was in sizzling style in Brazil, scoring herself two Best looks.  At the premiere of Knight and Day in Rio, the sexy starlet rocked a dangerously high-slit green satin mini, changing into a geometric print Givenchy blouse for a chopper ride later in the day. Beyonce jazzed up a jumpsuit with covetable Fendi Cinderella Lucite-platformed heels, while

Leighton Meester showed off a little too much of her black bra under a Proenza Schouler tie-dye tank.

What Girl Next Door made our list twice, scoring a Best and Worst look, while promoting her new book? Check out the gallery in Style to find out.