Taylor Swift turns 21 today! In celebration of the country music sensation's milestone birthday, we've picked out our 21 favorite red-carpet looks from her repertoire, and talked to the designers behind them. "Taylor has that extreme star quality," said Zac Posen, who designed her shimmery black halter dress (second from left). "Taylor always loves the 'wow factor' dresses, and wears them with style," British designer Jenny Packham, who designed the sparkly dress Taylor wore to a gala this year (above right), told us. We agree! Check out all 21 of our top Taylor Swift dresses—including her red Monique Lhuillier and white Ralph Lauren gowns seen above—in the gallery.