(Also, I know they are incredibly simple looking but that's the kind of style I like and I am not very good at doing hair :X)
Gorgeous side-swept hair from Rodarte Fall 2011
Kind of similar to this style that Blake Lively did...
Also, if you're interested, I found a pretty good tutorial on Youtube on how to get her hairstyle which you could make your own to resemble the Rodarte look
Loose pony tail/bun from Alexander Wang Fall 2011
Messy middle part/braid from Band of Outsiders Fall 2011
Loose braided pig tails from Rag & Bone Fall 2011
(images from style.com and vogue.com)