Several years ago, I bought a Lowe Alpine "Countour 40" daypack. It's a bit heavier than most (about 2-1/2 pounds) but fits well, has adequate padding against your back, has a waist belt to take some load off your shoulders. Dual ice axe loops (I often use the second to carry a camera tripod), dual bottle pockets on the outside, and an outside flap with straps that's designed to take a snow shovel but works great to stuff a rain shell or other garment. Just a main compartment and small zip pouch at the top of the pack.
Works for me...