The Pallisades packs are excellent quality, but it really depends on what you're going to do. If your main goal is to do day hikes, and maybe the occasional weekend overnighter, you would do better with a smaller pack like the Kelty Chuckwagon or the Ruff Wear Approach.
I have a Chuckwagon that I modified and I've been very happy with that, even for weekend trips. I haven't had a chance to test it for several days but I think it would have enough space to accommodate kit for a week, as the panniers expand. The modifications I've made are adding cinch straps to the outside of the panniers and adding web across the top so I can tie down a blanket or other small items.
Here's a pic of that pack, fitted properly and with the mods. The cell phone holder at the top is just to show how things can be attached to the web.
Most hiking and outdoor stores, like REI, carry the Kelty pack as well as the Ruff Wear packs, so you could go and compare them. The stores here no longer allow dogs inside, since April of 2007, but the store staff will bring packs outside for you to try on your dog. It's always best to try a pack to make sure the fit is great. Even the best pack may not work well on a dog that falls into an in-between size, for example.
REI also recently started putting out its own line of dog packs, the OllyDog Dog Pack. http://www.rei.com/product/759314
for info. I have not had a chance to look into that one personally, but it looks similar to the Uhlr Gear packs that allow you to lower the panniers on the dogs' side. I used to have an Uhlr pack - you can get them for about $10 on eBay, or new for about $25 - and they're a good starter pack if you need to get your dog used to a pack for the first time or if you need a cheap pack just for around town / exercise, etc. I used my Uhlr pack to get Abby used to it, then got the nicer Kelty one to replace it.
My next project will be making a completely custom pack for my dogger. A friend of mine gave me a rather torn up South African military load bearing vest and I'll be using the pouches and some of the webbing from that.
Just for fun ... trying to see if I can improve on backpack designs.