Any suggestions for a good backpack? I'm a soon-to-be 2L, and I'm still trying to find a good bag to carry my laptop and casebooks. I used a Targus backpack first semester 1L and a Booq Mamba Sling 2nd semester. Neither is very comfortable to carry when heavy. I want something that will protect my laptop, hold power cords and a few casebooks. I'm looking at the Booq Boa backpack with the Vyper sleeve for my Macbook Air, but I'm open to other suggestions. I want something that is at least semi-rigid with comfortable straps for the walk to school. Thanks!