I have an older model Patagonia Double Haul pack that has worked very well for the past five or so years. The back part of the pack fits on my back at an angle and even when I stuff the back section with a water bottle and a rain parka, the front pack stays put. One of the things about this pack that I really like is that I can adjust the straps so the pack stays above the water when I wade deep.
Waist packs a great as long as you are not wading in water above your waist.
Here’s the one I wear when I want to go minimalist. It has magnetic closures, which eliminate a lot of fumbling when you’re opening and closing up.
http://www.williamjoseph.net/product_details.php
I can’t seem to make the link work. Go to William Joseph. Amp magnetic.
This is what I use and i love it. I never use it as a chest pack only as the strap is uncomfortable on the neck. but it never rides out of position or slides up. I also wish the backpack had a bit of a bigger opening, but it is a very small problem.
I still have my vest but never use it unless I want to wear something while floating in my toon.
I highly recommend the double haul.
http://fishpondusa.com/doublehaul.cfm
Look not further LastChance…L.L. Bean’s Rapid River Vest-Pack for a mere $99. I suspect you noticed as I wandered all over the Lamar and Paradise Valleys last year with mine loaded down with 70 oz. of beer in the hydration bladder, three cans of mustad sardines, two cans of smoked octopus, two pears, one rock hard peach, L.L. Bean Stowaway wading jacket, Sunday Afternoon Cloudburst hat, several petrified rocks and a whisky flask, all in the backpack and it never inched towards by chiny chin chin. My huge Frabil landing net also hung from the pack. I will assure you, you will never wear a more comfortable pack vest. GUARANTEED. You have L.L. Bean’s and my word!
Hi Ed! Yes, I forgot about the gear you wore on our trip. It seemed to serve you very well even fishing-wise. You were a walking, talking saloon on 2 legs. We slayed 'em. I’m wondering, though, was the Bean vest/pack too hot?
P.S. I still have the same phone number and live in the same place.
Bruce,
I thought you told me you went FISHING!! 
Hi Betty! We fished hard and had fun, too. I just love a cold beer with a sandwich while I’m sitting near the river rehashing the morning memories.
Betty, hope you’re well!
Bruce
Like, NJTroutbum, I have purchased the Fishpond Blue River pack and really like it. I decided that I was carrying way too much stuff with me with other packs and never used most of it plus I studied how many times I would need anything out of a pack while fishing and decided that I seldom got into the pack for anything except a fly box when I wanted to change flies. I dislike a chest pack because it was always in my way when casting or it would obstruct my vision when wading/walking. I wear the Fishpond Blue River pack over one shoulder and it hangs off the opposite side under my arm. It has the waist belt which takes the weight of the pack off my shoulder. When fishing, I slide the pack to the rear where it is out of my way for casting and it does not obstruct my vision. When I do need something from it, I just slide it around to the side or front to gain access to it. I know this does not answer your question, but, it is what I found works best for me. For me, the backpack system would enable me to carry even more stuff I would not use while fly fishing and just add more weight to carry around.
