Osprey Farpoint 55L + detachable daypack
I adore this backpack. It's easy to carry, it's small enough to qualify as carry-on luggage, and being able to zip up the shoulder straps is a gloriously smart design detail. I also love the size limitation because it forces me to ship purchases home or to refrain from buying things at all. In addition to all that, the detachable mini backpack continues to be a great handbag on it's own.