If you're okay with the sporty look vs. the luggage/dressed up look:
The old (unfortunately discontinued) Arcteryx Blade 21 has been around the world with me and I wouldn't part with it for anything. You see new old stock pop up on eBay from time to time. Telling point: I have friends that work at Arcteryx that all seem to still favor and use this bag.
http://m.ebay.com/itm/Arcteryx-Blade-21-Black-Laptop-Nylon-Backpack-Arcteryx-/302334819882?hash=item46648f3e2a%3Ag%3A154AAOSwlMF ZLztf&_trkparms=pageci%253A52a867a2-4fc1-11e7-8c38-74dbd180fbca%257Cparentrq%253A9e7ef3e915c0a993ebcd ffb9fff7d02f%257Ciid%253A2
Their super high line Veilance pack is similar and worth checking out. Arc does a lot of very minimal stuff that keeps weight and fluffiness down but still feels comfy. I've got a few Arcteryx bags that I love for different purposes.
The Osprey Comet is a pretty darn useful small pack as well. I wound up upsizing and getting the Ozone 46 (their biggest "bookbag" style). But for the size you're looking for, the Comet has a lot of those great features in a smaller size. There's also a women's fit version of the Comet.
https://www.ospreypacks.com/ec/en/product/comet-COMETNEW.html