The Tech Sling from Aer boasts a solid amount of organization and space for loose gear. Features a space for a 13″ laptop.
Other Bags to Check Out:
The Everyday Sling from Peak Designs is a truly innovative, functional and delightful little sling with an insane number of thoughtful features for the size.
The Bravo 18 from Remote Equipment is a simple 18L bag featuring minimalist philosophies and strong design chops.
The Day Sling from Aer is a stylish smaller sling with a bunch of organization for minimal daily carry.
An extremely versatile and feature rich bag that doesn't look half bad, the Errant has lots of organization in an innovative pack for everyday use. One of my favorites.
The Aer Duffel Pack is not the tool for every job, but for particular uses it just might be perfect for you.