What used car models (1998-2005) will have the lowest insurance premiums in Ontario, Canada?

In Ontario almost all insurers use what is called the CLEAR rating system for vehicles. Every vehicle is assigned a rating for Collision, Comprehensive (these would reflect how expensive it would cost to repair the vehicle if damaged and it's relative value if it was involved in a total loss), and Accident Benefits (likelihood of being injured in an accident with that vehicle and the severity of injury in a certain situation). The Accident Benefits section of your policy (which is a mandatory coverage) is always going to be the most expensive part of the policy (unless you're talking about a commercial vehicle, which I assume you're not), therefore you want a vehicle with a good accident benefits rating. IMHO the best bet is a compact pickup (i.e. Ford Ranger) or compact SUV (i.e. Chevrolet Equinox). These vehicles usually have a good Accident Benefits rating, aren't that expensive to purchase and aren't too expensive to operate (as compared to a full size pickup or SUV).

Any used car that you can pay cash for, and thus not have to finance to satisfy a lender. Liability premiums won't vary by type of car (except sports cars) or age.