Here at FitSugar we are all about staying well hydrated on the trail. Wearing a hydration pack is way more comfy than schlepping reusable water bottles in a regular backpack, and the BPA- and PVC-free water reservoir of Verve 7 ($74) holds 2 liters (that's 70 ounces) of liquid. Better yet, it's designed for women — the fit is sublime, especially through the shoulders. Plus this has pockets for stowing tools and tubes making this a great pack for attacking the mountains on your bike. Pick one up at REI.