Another option is to put an old blanket or tarp on the back seat and put the bike there, on the floor, with the front wheel removed. Load it rear wheel-first from the driver's side. With some care, everything stays clean. Works for me.

I've gotten away from racks now because I drive a Prius and like to keep the aerodynamics intact. A receiver hitch on a four-cylinder passenger car just rubs me the wrong way, though I did consider it for the Prius. If I were going to load a bike frequently (I don't), that's probably what I'd end up doing.