I've had various styles of bike racks in the past, and now I've finally found one that is perfect for me, my girlfriend, and our bikes.
After picking up two full-suspension bikes, we were having some difficulty getting the old post style rack to work. We purchased the frame adaptors that attach to the seat post and steering neck. That idea sucked. The bikes slide around and parts of the rack would rub against the bikes' frames. Plus, my girlfriend had a hard time getting the bikes up into position on the rack.
That rack found the trash and we purchased the Thule TranSport T2 2-Bike Rack.
This rack is absolutely awesome. It comes partially assembled, takes minimal tools and 15 minutes to set up.
Now when it's time to go, we can have the rack in place and both bikes on, all in about 2 minutes. The best part is that my girlfriend can do it just as easy I can. On days that I'm not around and she wants to ride, that works out nice.
The rack is durable and easy to use. I highly recommend it; A+.