Wool is indispensable, in my opinion, but you still want some sort of shell to maximize water shedding.
What I've settled on after years of experimentation (not saying it's the best, but the best for me so far) is wool clothing with a light, breathable water-resistant shirt and overpants, covered with a water-impervious poncho. I don't care about the breathability of the poncho. I gave up on pack covers long ago and switched to pack liners. In my case, I just use a large contractor's garbage bag for that. It's heavier, but the ruggedness is worth the weight for me and what's inside will stay dry even if I fall into a lake or something.
Usually, my feet get the wettest in rain, and is the most miserable body part to be wet, so wool socks (with sock liners to prevent blisters) and waterproofed boots are mandatory. Wool socks dry very quickly. I haven't got a great solution to keep the insides of the footwear dry (shoes/boots don't dry quickly without a boot drier and you have to be shoeless while drying them), but gaiters really help a lot.
What I've settled on after years of experimentation (not saying it's the best, but the best for me so far) is wool clothing with a light, breathable water-resistant shirt and overpants, covered with a water-impervious poncho. I don't care about the breathability of the poncho. I gave up on pack covers long ago and switched to pack liners. In my case, I just use a large contractor's garbage bag for that. It's heavier, but the ruggedness is worth the weight for me and what's inside will stay dry even if I fall into a lake or something.
Usually, my feet get the wettest in rain, and is the most miserable body part to be wet, so wool socks (with sock liners to prevent blisters) and waterproofed boots are mandatory. Wool socks dry very quickly. I haven't got a great solution to keep the insides of the footwear dry (shoes/boots don't dry quickly without a boot drier and you have to be shoeless while drying them), but gaiters really help a lot.