The slick, black Cadillac of racks is the Blackburn TRX-1 Ultimate Touring Rack. It's 6061 aluminum, so you know it's light and strong. It holds a ridiculous 40 lbs, has a narrow center of balance and can take panniers on high or low mounting points. It's designed especially for road (700c) bikes, so if you want to get your tour on in comfort and style, take a look at TRX-1.
14mm gauge aircraft quality 6061 aluminum rod for uncompromised strength
Narrow profile for better balance
High and Low pannier mounting points for versatility
Designed for 700c bicycles--especially for touring