For many Hollywood elite, the Cosmopolitan of Las Vegas -- the city's newest and most glamorous resort -- was the most stylish spot to kick off 2011.

The grand-opening celebration included concert performances from Jay-Z and Coldplay, plus surprise guests Kanye West, Beyoncé and John Mayer.

Our favorite look from the event had to be "Sex and the City" star Kristin Davis' ankle-length purple Prada frock with plunging neckline. The 45-year-old's vibrant dress was matched with a pair of nude Brian Atwood slingback peep-toe platform pumps and clutch.

In related news, Davis' "SATC" co-star broke our top 10 fashion moments of 2010.