Fjallraven High Coast 26L Trail Pack

There's a lot to like about this backpack. It's easily the most comfortable pack I've ever owned. It's big enough to a Pacific NW day hike (meaning, you know you should pack some rain gear, gloves, and a hat on nearly every hike) and has plenty of room for a couple of quarts of water, some snacks, and the rest of the essentials (bug repellent, knife, camera, etc). They make some smaller versions that are great starters for introducing your kids to hiking.