I live in NYC and have a 30 minute walk to and from the office each day. I love to bring my 15" MBP with me, but on days when I do my back really suffers. I've tried a few different bags and I can't quite find one that helps mitigate the back pain. I usually use a Crumpler Sinking Barge but I bought a BBP bag a couple of weeks ago based on their claims of being more ergonomic, but sadly I found that to be just as painful. If anyone has any recommendations both my back and I would be quite grateful. I wouldn't be opposed to a rolling solution, but I would need a case that could handle the shocks and bumps of nyc sidewalks. thanks!