Ah, the roof rack. Prepare to spend hours figuring out what components of what system will work on your vehicle with what equipment carriers, and then break open your bank account to pay for it all. We're nonetheless pleased to report that after this painful process we found a roof rack that we're happy with: the Thule Aeroblade system.
For our 2012 Jeep Grand Cherokee with factory rails we needed three things from Thule: bars, feet and fit pack. We chose the AeroBlade bars because they're strong, quiet and they look cool. These are the bars in the top two pictures. The bar shown in the bottom picture is the AeroBlade Edge, which is an all-in-one system that doesn't require separate feet. Also available is a contractor bar that's even beefier.
The AeroBlade recommended for our vehicle was the 47" width, but looking around online we found that we could go a step up to the 53" bar and get a bit more usable space. It mounted fine on a set of Rapid Podium 460R feet attached to the Podium fit kit. Total cost: about $425. Using our 20 percent off coupons helped, but this is still a hefty expenditure, more so considering we can't actually carry anything until we add the appropriate carrier.
That said, we were looking for a solution to mount a roof box (review to follow) so we could throw in a Chariot child carrier, skis, backpacks or whatever else we wanted to cart around for a family of three plus guests. The Jeep is an awesome four-wheel drive vehicle, but interior cargo space is limited, especially when you've got a child seat in the back.
Now, we have to say we love it. It's quiet at highway speeds - we don't even notice any additional wind noise - and it'll mount a roof box and kayak carrier side by side, still leaving room for our hitch-mount bike carrier. The only caveat is the instruction manual, which uses only pictures to guide you to a state of screaming frenzy before you just dive into it and figure it out. It actually doesn't take that long, but beer really, really helps the process go smoothly. Crappy instructions aside, we can highly recommend Thule gear in general and the AeroBlade system specifically. This is a case of getting what you pay for, which is really all you can reasonably ask.