If you own a garage, DO NOT buy the roof rack. It seems ridiculously obvious, but it's happened to most everyone at some point. You come home, tired from a long ride or trip, and WHAM, Crunch, Ouch. Your $5,000 dream machine is sheared on the soffet of your two-car.
Now if you don't have a garage, then this will probably never happen to you. However, don't sweat the hatchback thing. My Yakima has a simple pin that disengages and the rear rack folds down to let me in the trunk. Just make sure you buy one with a locking bolt and locking cable. I love the fact that I can see my titanium baby in my rear view mirror at all times. It stays remarkably clean back there as well. I've had my rig on my buddy's van on a couple of trips and even without rain or weather, the bike just looks a little worse for wear.
Make sure the hitch and rack are installed professionally. Also make sure you document the installation (with pictures) for the insurance company. In the unlikely event you mash your steed, the insurance company will play hardball and will probably try to discount your claim by saying that the rack wasn't professionally installed. A good riding buddy of mine happens to be my insurance agent and he tells me that he has to turn down claims all the time due to shoddy rack installations and lack of documentation of a "professional" install. Have the LBS, U-Haul or car dealer put the thing on so that you know it's done right. Best of luck.