Ask nearly any photographer what one thing they're most likely to spend money on, and not be happy about, and there's a good chance they'll tell you the item is their bag.  It's bags; not lenses, not camera bodies, not remotes or triggers, that seem to constantly be "improving" and yet never seem to satisfy the average photographer.  Sure, some might tell you, "Well, I love my Timbuk2 Messenger Bag" or, "I don't go anywhere without my Lowepro Slingshot!" but talk to them for a few minutes and there's probably something that bothers them about their bag.  Something that just doesn't seem to fit right, or sit right.