Noise, yes. Bear spray- yes. You can buy it here, at any sporting goods store, Wal-Mart, Fred Meyer. I don’t think you can take it through Canada…at least, I know the last time I went through Canada and they found out I was from Alaska I got the third degree about any type of weapon and bear spray was on the list. We Alaskans apparently have a rep.
Make noise, as David said. Talk, sing, call out “Hey bear!”, bang on something, wear bear bells, etc. Be especially careful – and noisy- in heavy brush and near running water (because running water can mask noise quite well).
I didn’t get the impression you planned on carrying a firearm but my opinion is different than David’s on firearms. I carry bear spray as my primary defense, with a gun as secondary. IMO, bear spray is great if the bear is downwind, and if you’re not in your tent. Not so great if you’re in your tent or if you’re the one downwind. Guns also make a nice big bang, and I think there’s a reason why people in Canada use bear bangers. Just my opinion. You’ll probably run into other people who are packing, it’s pretty common up here.
Electric bear fence are used by hunters up here. Not typically by backpackers, but I suspect that’s more to do with weight than anything else. I think they are probably fairly effective.
I suggest you eat well away from where you camp. Not just in terms of meters, but rather miles. Stopping an hour before you plan to camp to make and eat your dinner keeps the smells away from your camp. Barring that, eat and store your food well away from your camp. A couple years back I was camping with a couple other ladies above treeline in the mountains, well away from any salmon streams. It felt pretty safe- never saw any bears, or bear scat, it wasn’t berry season yet. We cooked and ate about 50 yards from the tents, and stored our bear cans well away. While I was eating, a tiny piece of food fell off my spoon and onto the ground. I didn’t think much of it. The next morning I walked back over to where I had eaten the night before- only to find a HUGE hole had been dug. We never saw or heard a thing over night, but clearly a bear had come into camp and had found where I’d dropped that food and had been hoping for more.