Hi PFers! I am thinking about buying a messenger bag, preferably oversized, but am wondering about a few things concerning it: (a) does it have to be a flat bag, or will any bag that has a long strap when worn over the body, be alright? (b) are they a fad or kind of on the classic side? (c) have any of you seen some particularly great ones? (d) I have seen them worn across the body with the bag part in back, almost covering one derriere cheek is that the way they're supposed to be worn? its at the point now where I won't buy a bag until i have checked with you all LOL Thanks so much for any input!