I use my roof rack mostly for my kayaks, I have a Yakima q-tower set up on a 2002 Neon, and its rock solid. I take the rack off when I am not using it, because it takes all of 2 minutes to put back on. I like the round bars, unless your roof is perfectly flat, Thule bars could cause mounting problems.
For a bike carrier, I use a RockyMounts noose, for roof mounting, and a Yakima 3 bike trunk mount, an older version of the King Joe, thats not stainless... Bought it at a yardsale for $10 and it was hardly used, still had the $120 price tag on the box even
I personally prefer the trunk mounted bike carrier. Not sure why, I just do. I think I used the noose 3 times...
For my kayaks, I use plain foam blocks that slip on the bars for the 13.5' tandem, and Thule j-cradles from dick's sporting goods for my 11' fishing rec kayak. The j-cradles and my Neon's low roof make getting the kayak up there a breeze. When hauling kayaks, bow and stern lines are a MUST! in case of rack failure, they will keep your kayak from venturing too far off your car.
I would really stick with a trunk mount bike rack though. You get more capability for the same money, and the Yakima Joe racks are very stable and strong, my brother took 3 heavy cheap bikes camping and drove probably 300 miles round trip without problems, borrowing my yakima trunk mount bike rack.