I just got my PB 15 and am looking for a good bag. I will also be carrying a camera (digi-SLR) and school books in it. does anyone have experience with the Crumpler bags? Specifically the "formal lounge" or the "sheep scarer"? How about the messenger bags, are they better than a backpack? Are the bags heavy? Do they protect the notebook well enought? thanks in advance. PS I'm pretty small, (5'2") so i want a bag that's not going to hang to my knees and won't be extremely heavy.