Macpac Esprit 65 FL
Here's what other sites are saying:
There's a reason the Macpac Esprit 65L Pack has a system called the Freeload, and it's not because this pack'll sleep on your couch and eat all your food. This weatherproof backpack has a women's-specific design that moves weight off your butt and onto your hips. The long, flared hip-belt slides over your hips, narrow, close-together shoulder straps fit your torso, and flexible aluminum shoulder tracks stabilize your load while allowing the backpack to move with your hips. Leave the rods in a neutral position when you're scrambling up steep terrain (more weight on your shoulders for better balance) and crank the rods up into full position for weight transfer onto your hips on neutral ground.