Flesh Tone.

Katy Perry, Kristen Stewart, Louise Roe and Lauren Conrad have impressed on the red carpet by stepping out in flesh colored /nude dresses.
Whilst kristen Stewart’s lace confection at the premiere of Breaking Dawn part 2 left little to the imagination with its transparent lace on bodice corset and a long skirt, there are a lot of beautiful dresses in nude with less daring. Take Zoe Saldana's dress.
If you do not want to give the illusion of nudity opt for a neutral coloured dress a little different from the skin.

From L-R: Katy Perry, Kristen Stewart, Zoe Saldana and Gillian Anderson