Mammut Creon Zip 28
Here's what other sites are saying:
The Creon Zip is a modern and stylish hiking and daypack. The circular zip allows direct access to the main compartment, while the air space suspension system allows excellent ventilation from all four sides. The unique "chimney effect" helps to prevent annoying perspiration.
The Mammut Creon Zip 28 backpack has a super-clean design, but that doesn't mean it's a minimalist's dream; it has everything you need for a day hike, like a wide-opening circular zip, integrated and detachable rain cover, and a design that's compatible with whatever hydration system you use. If you're not using your trekking poles, just strap them into the side carrying system, slip your water bottle out of the mesh side pockets for a quick sip, and get a move on before the storm hits. You'll be cool even as you're hauling down the mountain, because the Creon has a 4 Stream suspension and ventilation system that keeps the pack riding close to your back, while allowing warm air to rise and cool air to take its place, so you won't get uncomfortably sticky.