I had a Saris Bones rack on my Mini and liked it well enough. It had a tendency to loosen up a bit over long trips with two bikes on it, though.

When I got my Prius, we installed a hitch ourselves and then used the hitch rack we already had for our other car. It worked great! (killed the mileage though!).

Check out http://www.etrailer.com/ That's where we got the hitches for both the Prius and our Matrix. Super quick shipping, too.