The “Sensitivity V” laptop backpack certainly stands out, with a droop shoulder design and S-curve asymmetric back pockets. And though it might be a little aggressively sporty for all tastes, it does look modern without looking totally overwrought, in large part because of its relatively small size. (I could do with slightly less prominent rubber fobs, but that’s the way it goes.)
It’s only about $80 from online retailers, too, which isn’t too bad. I’m in the market for a new backpack (still) to replace my weathered Gravis sack, but I’m trying to find something that is sturdy that would look okay with slightly nicer clothes than normal. I know shoulder bags are much more classy than backpacks, but they just don’t work for trips as well as backpacks. Basically what I want is something like this very bag, but in soft leather. And I’ll never find it.
Kata Ergo-Tech Sensitivty V backpack catalog page [Amazon.com via Core77]



Take a look at the Timbuk2 Hacker backpack. It’s a bit spendy at $120, but its simplicity in looks may be what you’re looking for. Also converts to a shoulder bag.
also consider making or commissioning your ideal bag – those etsy types will make anything!
It may be out of your price range, but for something I’ll use for years it is worth it. Check out the Vivsim Ballistic 20: http://www.bridgefootwear.com/product_info.php?products_id=7496&img=8&osCsid=6ci5lneauqn3ujvpk5irq8s3r6
It’s got a leather bottom, so not completely leather, but it’s stylish and high quality.
I have this bag and I love it! It is perfect for carrying my laptop (15″ Mac Book Pro) and dSLR. The top compartment also conveniently fits enough clothes for it to work as a weekend pack. The only downside is that it doesn’t fit books or other large objects well. I can normally squeeze a paperback or two in the back compartment with the laptop, but it is a bit uncomfortable when I do.
Gravis has a bag for you….
http://www.gravisfootwear.com/Products/default.aspx#/bags/mens/90683
Regarding shoulder bags versus backpacks:
Whether they are stylish or not depends on the message they send about their owner.
A shoulder bag says: “I’m young enough to not care about my back” or “I’m traveling light, so I don’t need to worry about my back” or “I’m to old and set in my ways to put my own well-being ahead of social norms”.
A backpack says: “I need both hands free” or “I put my well-being ahead of social norms” or “I’m carrying heavy stuff” or “I care about my spinal column”.
Me? I’ve got a Caribee backpack myself. Comfortable and high-quality with generously padded respiring back and shoulder straps. It’s worn, smudged and slightly frayed at the edges, which means it, and its contents, is unlikely to get stolen.
It comfortably fits a 15″ laptop, mobile phone, camera, a couple of large books and a change of clothes. All I need for a weekend trip or a short conference.
The Kata backpack looks nice, but I wonder how practical the s-curve back pockets are. Won’t they be hard to reach if the backpack is placed on the floor and you are reaching down to retrieve something?