Can a running-oriented hydration pack double as a daypack? Yes, if it's designed as well as this one. During trail runs in the mountains above Santa Fe, the Riff's compression straps, foam back panel, and perfectly sculpted harness made for a stable, slosh-free ride. Yet on hikes the Riff still had enough space to stash storm gear and a lunch. Light and weather-resistant siliconized nylon keeps weight down, while an external daisy chain, tool attachments, and side pockets increase versatility. 15.8 oz, 900 cu in; mountainhardwear.com
Bonus: The minimalist design sneaks in a small top pocket for sunglasses or MP3, and still doesn't break a pound.
Bummer: Avoid overpacking; the thin foam back panel can bulge under full or awkward loads.