Dog Backpacks by Outward Hound
If you've seen Cesar Milan's Dog Whisperer series, you've probably seen him bring the backpacks out for dogs who need a bit of help on the outdoor walk front. If you've watched him do this, you've probably been amazed at least once by how remarkable the changes are in the dog's behavior once they have a dog backpack on. Working dog breeds do particularly well with these pooch backpacks and I say this from personal experience -- the changes are positive, immediate and long-lasting. If you've got a dog who seems a bit difficult on a walks, get him a backpack and marvel at how obedient he becomes when he has a job to do (carrying his backpack)!
And once they've got that behavior under control, future walks without the backpack will be just as easy-going, relaxed and fun. You don't need to put anything at all in the bags, and you surely shouldn't weigh them down too heavily, but added a little bit of weight can help your dog get more exercise out of his usual walks, and a tired dog is a relaxed dog! Personally, I like to stick a paperback book in each pocket; just enough to give it some weight, but not much more than that. Some people like to fill the pockets with sand, which is fine too -- just remember, these aren't necessarily built for carrying something as heavy as water or other things of that nature. If you're taking Fido on a major hike that requires all kinds of crap, hauling it is your job, not his!
Excursion Dog Backpack
I have this model, and I can tell you it's FABULOUS. The Outward Hound Excursion Dog Packpack is probably somewhere in between the other two models. It's high quality construction, easily cleaned thanks to the nylon exterior, is totally water resistant (I keep a paperback book in each pocket for a little added weight for exercise and the books have never gotten wet in the rain), and has a comfy pad that sits between the body and straps. That said, you can't fit anything like a water bottle in the pockets of the medium sized version; this isn't for proper camping, but more like a good walk.
Outward Hound Backpack
Outward Hound makes fabulous, fabulous dog backpacks. This one in particular comes in several colors: Black, Blue, Green or Red. The pack itself is removable so if Fido needs a break at some point you can take that part off. There are reflective safety strips on the side and the straps are fully adjustable. Be sure to measure your dog and check the size chart to determine which backpack is most appropriate for him.
Urban Adventure Backpack
This Outward Hound Urban Adventure Backpack is a simpler dog backpack, designed for use on trips to the local park or around the neighborhood. You can store treats and bags and the like in the pockets, but it's not intended for hauling big water bottles and other things you might take camping. If you need something more involved, see the previous model.