I lived and worked in Ottawa (Canada) for five years without owning a car. I rented a car fairly frequently on weekends, and when needed I rented a pickup truck, cargo van, cube van, etc.
It worked really well. I took the bike or bus to work and to downtown most of the time. When I needed a vehicle, I rented one. My rental costs were *far* less than it would have cost to license a vehicle and pay insurance on it, much less buying/leasing one.
Now I've got two kids and live in the prairies. Public transit sucks, so I own a smallish car. But I've still rented a van for a long trip with relatives.