I would recommend the LL Bean Rapid River Vest Pack
I own quite a few vests and fishing packs. I have three larger packs, and three vests, and a couple of small shoulder packs. The Rapid River Vest Pack is the one I use more than all the others combined. It has a number of features that make it my favorite. First off, it has excellent capacity. The backpack portion is expandable, and will hold enough stuff for a whole day of fishing. You can put your lunch, a 3 quart water bladder, rain jacket, and other assorted necessities in this pack with a bit of room to spare.
The front part of the pack, which is designed to hold your fishing tackle, is very well thought out. There are two large pockets sized to hold big fly boxes, and other pockets to hold tippet, strike indicators, etc. There is enough storage space to carry everything you might need to catch fish. There are a couple of built in retractable "zingers" to secure your nippers and hemostat. The best thing about the front gear storage is that it is distributed widely across your torso, so that it doesn't create a big protruding lump on your chest that interferes with casting and being able to see your feet.
Even fully loaded, this vest/pack is very comfortable. The combination of the vest, shoulder straps, and hip belt distributes and controls the weight better than anything else I've ever used. The hip belt, in particular adds to the comfort of the pack, both with weight distribution and also lending some back support for long days on the river.
The vest provides decent ventilation for a pack of this type. I use it in the heat of the summer with no issues.
As much as I like this pack, it isn't quite perfect. First off, the back pack part could be a lot bigger. It's not quite big enough to comfortably stow neoprene footed stocking foot waders. Certainly, the weight bearing features of this pack make it easily capable of incorporating a much larger capacity back pack. If the size of the back pack were doubled, it could then hold your waders for the hike in, along with everything else needed. This seems like a serious design oversight to me. I don't know why the designers did not think the make the pack large enough to stow waders.
It's also a bit heavy and bulky when compared with a lightweight vest. I wouldn't want to pack this in on a long, multi-day backpacking trip. It just weighs too much and takes up too much space to be a good backpacking fishing vest.
The other shortcoming if the pack is perhaps an inevitable result of its design. The lower pockets tend to get wet when deep wading. The pockets are not placed particularly high, and the waistbelt and lower part of the backpack tend to become submerged when wading much more than waist deep. To counteract this, I use waterproof fly boxes, and store any water-sensitive items (like my lunch) in waterproof ziplock bags.
Overall, however, I really like this pack. For long days on the water, when you're hiking in and hiking out, it's hard to beat. At under $100, it's also a bargain.
Rapid River Vest Pack: Fishing Vests at L.L.Bean