I live in Seattle. Where my house is, there's plenty of street parking, which is nice because I do own a truck. But I almost never use my truck to run errands or commute within city limits. Driving in Seattle pisses me off, parking in Seattle pisses me off, my bike times are usually about equal with my drive times, especially after hunting for parking, and I'm sure I'd have finished killing my clutch by now if I drove on city streets more regularly. Running errands on a bike is pretty awesome too, if I don't have to carry anything bulkier than a bag of paper towel rolls (I can fit six rolls in my messenger bag, just) or plan for the heavy/bulky item to be the last stop, and strap it to my rack. Instead of that process of drive somewhere, find a parking space, park, walk back to wherever, do the errand, walk back to the car, drive to the next place, find a parking space, repeat, it's just ride from place to place. Sometimes I don't even have to lock the bike.
I do also save a lot of money. Not sure how much, since I don't think my miles would go up that much if I didn't ride my bike (my insurance is for a certain number of miles a year, and driving to races accounts for a hefty chunk of that) but my commuter cost $95, and the biggest expense I've ever had since purchase was building a new rear wheel several months ago for $60. By contrast, it costs almost $60 to fill the tank in my truck, and things like brake work, a new windshield, and new rear tires have all cost more than my entire commute bike did.