Osprey Stratos 44

Osprey says:
You take your hiking seriously and like to stretch your day hikes into light overnights more often than not. The Stratos 44 is built for rugged trails, rain or shine, with serious features and a top loading design so you can easily pack up and go. It's a sustainably designed technical pack with a cloudlike carry, thanks to its highly ventilated AirSpeedA(R) suspension system. And even when things turn stormy, your gear is covered with an included raincover.