I have never personally had the need to buy a roof rack but i used to be 4 wheel drive parts salesmen. For the two years i did that we seemed to get a lot of positive feedback from customers about Garvin wilderness racks. they have a few different styles to choose from http://www.wildernessracks.com/ Also, ARB 4x4 makes some nice racks, even a rooftop tent! http://www.arbusa.com
However i should warn you, these two companies' products are notoriously expensive, but you usually get what you pay for.
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