Helly Hansen Impertech
Up in Alaska, for instance, Helly Hansen's Impertech Jacket ($70; www.hellyhansen.com) is a popular choice. It's not breathable, but it's tough, fairly light, 100-percent waterproof (and windproof, of course), and stretches for comfort. It vents through a back "cape" opening. Matching pants are $55, so for $125 you have a good rainsuit for the conditions you'll be facing.
The alternative is something in the waterproof-breathable arena. Arc'teryx's Theta AR Jacket, for instance, is made with Gore-Tex XCR and has reinforced patches for increased durability. I think it would be tough enough, and its generous, long cut would keep you dry. But it's also $450 (www.arcteryx.com). More affordable is REI's Taku Jacket ($199; www.rei.com), a non-Gore-Tex piece that I like very much. I worry a little about its durability in a high-impact environment, however. But it's light, sheds rain well, and is wind-proof, so there's that. Mountain Hardwear's Exposure II Parka uses that company's own proprietary waterproof-breathable material, has reinforcements for rugged conditions, and sells for $200 (www.mountainhardwear.com). Maybe a better choice in the higher-priced stuff.
Myself, I'd give the Helly Hansen stuff a close look. You may sweat a little if you have to portage in the rain, but if you're stuck in a canoe in a downpour, I can guarantee that it won't leak.
For more expert reviews of the toughest jackets and raingear, check out Outside Online's Jackets Buying Guide.