I'm not a big spender, and I rarely transport my bike more than 20 miles, so a strap-on trunk mount is all I need. Mine is a SportRack -- cheap, easy to install and use, and so far very durable and reliable. For security, I cable lock the rack to my station wagon's roof rail and then cable lock the bike(s) to the rack. So far, no thefts, and no damage to bikes or the car.
Overhead racks give me the willies. I used to work in a provincial park campground, and I've seen what a gatehouse roof overhang and a forgetful driver can do to a pickup camper -- or a couple of nice bicycles.