Joss - historically, variable has beat fixed hands-down. Your risk is that if interest rates start to move up, you need to consider how easily you can lock in. And remember that the locked-in rate will always be higher. Variable "pays" you to take the risk, fixed "charges" you to avoid it. Lots of lenders offer a blended version in which you can move from one to the other without penalty.
It is a very interesting time, mortgage-wise. We're at record household debt levels, mostly because people have borrowed beyond their means for housing. The banks are seeing the cooling off in the housing market and dropped the lending rates to an all-time low.
This cannot have made the BoC head very happy. Mark Carney can only keep interest rates low for so long, as inflation is starting to creep into everything else (anyone else notice things at the grocery store getting more expensive?). Once he moves that rate back up, there is serious concern that a lot of people won't be able to make their monthly mortgage payments, as they borrowed at the peak of their debt-servicing ability and don't have any wiggle room for increases.
It is somewhat regional, but housing is considered to be 25% overvalued in most areas of Canada. The correction has already started in some of the really over-priced places and is expected to be a bit of a shocker this spring. I know that I've noticed significant price drops in the areas in Calgary that I've been checking out. Still not enough for me to jump in, but it's getting closer.