Bike carriers

I looking to purchase a new bike carrier for my car, since the one I use was cheap and I am afraid that my bike will fall off. I currently use a trunk mount model on my Honda Civic. Are hitch models more secure? (I don't have a hitch on my car, but they don't look to be that expensive.) Would a hitch carrier look really odd on a car? If I need to stay with a trunk model, are there any that are more secure than others?

Any ideas are greatly appreciated.