Letsee.. of course there are those branded sites like
Hollister Co.
Abercrombie & Fitch
I also like shopping around:
Wong Fu Store - Welcome (What more can I say? <33333)
Woot Shirt : One Shirt, No Shoes, No Service (SM) (Most of the time, they have the most cutest shirts ever.)
YESASIA: Online Shopping for Japanese, Korean, and Chinese Movies, TV Dramas, Music, Games, Books, Comics, Toys, Electronics, and more! - Free Shipping - North America Site (Of course :])
AsiaJam.com - Asian Fashion, Japanese Street Wear & Accessories - Japan Kawaii, Korean Teens, Hong Kong (Somewhat like YesStyle)
I think my list goes on, but these are the main ones that I go to, and I think that hasn't been listed yet.