Lifehacker this morning pointed to an interesting article that listed 10 Handy Numbers to Save in your Mobile Phone -- it's an American list, so they don't all apply here, but it is a good place to start.
I have travel numbers in my phone -- but not airlines, as the list suggests. Instead I have the local transit "Busline" (so I can call when my bus is 10 minutes late and find out if I should start walking) and BC Ferries to check for delays, wait-times, and even make a reservation if need be -- it came in very handy when we had to check sailing times for the Mill Bay Ferry and change course when returning from Nanaimo due to heavy snow on the Malahat.
I have work and home numbers saved but they aren't labeled as such... maybe they should be. When I worked at the front desk, I used to check for a "home" listing in lost phones to try and get them back to their owners.
I don't have a locksmith listed, but I do have our family doctor, dentist, a vet, two taxi services, two take-out/delivery restaurants, and our mechanic listed.
It probably is a good idea to store the generic emergency lost card numbers for credit cards -- I'll be adding them later. Visa: 1-800-VISA-911 (1-800-847-2911) and MasterCard: 1-800-MC-ASSIST (800-622-7747) both numbers work in Canada and the US.
I'm not sure if Google's 411 service or SMS search work in Canada, but they are also worth testing.
One last important number: poison control.
Any other ideas?