A tow bar mounted bike rack is a secure option if you've got a good solid tow bar on your car, and the Thule EuroClassic G6 LED 929 3 Bike Towball Carrier is a fantastic alternative to roof mounted racks which can be tricky to load and can interfere with fuel consumption.
Thule are known for producing some of the most impressively engineered racks on the market, with designs for every possible type of mounting option. The 929 Euroclassic G6 is a flagship model, with a good number of bells and whistles and even more available as optional extras.
The Saris Bones 2 isn't just the best looking bike carrier, it's also one of the best at actually doing the job.
The Saris Gran Fondo is a very fine rear mounted rack for taking your posh bike to the sportive or crit. If you have a big stable of disparate bikes then it might not be the right choice, but as an easy-to-fit solution to carrying your good bike it's a well-thought-out, if fairly expensive, option.