I like hitch-mounted racks the best as they have a solid attachment to the car without touching the paint. Trunk-mount ones are good but you need to make sure the pads that touch the car are clean, the car where the pads touch is clean and you install correctly.
I've got a Yakima Kingpin hitch-mount, Yakima trunk-mount and a set of roof racks (that mount on the factory rack on my van). I'd keep an eye on Craig's List as it seems trunk racks come up often. I paid $10 for my trunk-mounted one and $50 for the hitch-mounted one. Both were virtually new when I got them.