Kate Spade's design sense is always impeccable and now it is translated into a beautiful website called "Behind the curtain." It has a nice mix of readable content plus some great eye-candy. (Found via Oh Joy! who is doing a fantastic job of guest-blogging at Design*Sponge.)
Another great fashion-oriented site is Isaac Mizrahi's Style Book, which offers a preview of the inaugural issue of his print magazine. You can download the entire magazine from the website, since his mandate states "Style is free!" Unfortunately, the actual magazine design isn't as elegant as the website.