Certainly the Expressway from Thule ($299, for 1.25- or 2-ince hitches; www.thule.com) has to come to the top of most heaps when shopping for a hitch-mounted bike rack. Its sturdy, carries four bikes, and has features such as an integrated locking cable. I havent used the anti-sway feature on the Thule, but it should work well, and in an event it seems like an extra bungee cord or two never hurts. The one thing Id caution you over is to think about tailgate access. The Expressway is a swing-down design. The somewhat more expensive Trailblazer ($399make that quite a bit more expensive) has a swing-out design that makes it easier to get into the back of an SUV or minivan.
Otherwise, there are the usual suspects for hitch racks, which have reached a fairly high level of sophistication. Yakimas Backswing ($350; www.yakima.com) holds four bikes and has the swinging-arm feature for good trunk access. Their stuff is always first-rate. Its also well worth your time to take a look at the Softride Access HD Rack ($319; www.softride.com), a very tough rack that pivots down, rather to the side, for easier access and to simplify loading. Softride also uses a dual-post construction in the upright arm, which could yield a stronger system than the single-post system used by Yakima and Thule, although those companys offerings are really plenty strong.