It’s war! Okay, not really. But here are a few unabridged thoughts on East Coast vs. West Coast style (the succinct, edited-down version can be found at Teen Vogue—link above):

• On-the-go New Yorkers may typify effortless style, but it certainly isn’t careless; it is thoughtfully devised to carry them from work to play, night to day, and equipped with enough layers to face the Northeast’s fickle elements.
• Casual, off-the-cuff elegance—perhaps first exemplified by Claire McCardell’s “American Look”—pioneered New York’s unique high-low and democratic aesthetic, as epitomized by McCardell’s then groundbreaking notion to don ballet slippers as everyday footwear.
• While “Boho” is a decidedly West Coast phenomenon, the manifestly New Yorker styles encompass Wall Street “business” (think Working Girl), Upper East Side “prep” (now ubiquitous with Gossip Girl), St. Marks Place “punk” (drawing its roots from the New York Dolls era) and a distinct ladylike “elegance” (legendarily exemplified by Breakfast at Tiffany’s).
• Red carpet-wise, New Yorkers are much less about showmanship (generally no “shoulders back and smile!”) since we have a less operative role in the entertainment industry. Our event attitude and outfit choices are more in the spirit of having a good time and derive from less of a see-and-be-seen mantra—as characterized by the breezy nonchalance of Chloë Sevigny, Alexa Chung and Michelle Williams.