Fashion's defining moment? You decide.

What was fashion's defining moment? Jackie's trend-setting appearance at the 1960 Presidential inauguration? The launch of Marc Jacobs' infamous 1992 "grunge" collection? Grace Kelly's debut of what came to be known as Hermès' "Kelly Bag" in 1956?

Women's Wear Daily is trying to decide ... and they need your help.

Each week, the site will put 25 potential "fashion moments" up for your consideration. You can vote once a day, and each time you'll earn a chance at a $2,500 designer handbag, a $1,000 AmEx gift card and an Apple iPod Touch.

Every Monday, you'll get to see the previous week's top vote-getters. Then, beginning August 25, the most popular 15 will compete to be named Fashion's Defining Moment, which will be revealed on September 2.

Cast your vote today—and every day—to play your part in fashion history ... and get a chance at some fab prizes along the way.