etrailer.com is a good site. I just bought my first new car on Saturday and ordered a hitch for it.
I've been selling the Swagman XTC2 bike rack for a few months and it is the overwhelming favorite of all hitch-mount bike racks. I'm getting one for my car. Roof racks impact gas mileage, they whistel, and you can feel them sway if you don't corner gingerly.