It's nude on nude!
Lots of rib cut-out and asymmetrical detailing, the color orange (gah!) and blue in shades of faded denim are prominent. Combos of black-white design and material patterns are also easy to spot. But it's nude, to me, that screams loudest this Spring/Summer 2009.
(Could nude be the new black?)

Nina Ricci

Zac Posen

Lanvin

Calvin Klein

Proenza Schueler

Stella McCartney
Image Source: style.com