For years I used a muli-compartment pack from MEC. I love all the compartments, I can keep everything super organised. For summer and fall fishinh when the weather is beautiful this is my pack of choice. However for winter steelheading it sucks. In heavy rain eventually the entire pack is water logged I boughy a rain cover for it but honestlu it's such a pain takinh the cover on/off I decided to invest in a waterproof pack. The only decent one around seems to be the Simms Rolltop. The main compartment is 100% waterproof which is what I wanted.
Careful with hippacks and other packs that look waterproof but do not have a rolltop closure. I bought the Simms Drycreek hippack thinking it was waterproof. After a few outings in heavy downpour I found out that the bag its self is (it has a rubbery coating) however the ZIPPER is only water RESISTANT. The result of this is the bag slowly filled up with water and saturated everything! I returned thr bag to where I bought it with no issues.
I would highly reccomend the roll top Simms. Yes it's pricey but the construction is top notch. I keep all my extra lures, line, clothing, food/thermos, etc in it. In my wading jacket I keep the bare essentials like my leaders, some extra lead, etc. It is a system that works for me. It nice to come home from fishing, open up the bag and everything is bone dry.