ARB has a rack that fits well on an XJ. I think it is the best looking, and possibly the highest quality rack out there, but it lacks some utility, comes at a high price tag, and might have poor availability.
Wilderness racks are (last I knew) of good quality, are modular, and offer a large amount of utility with the availability of numerous bolt-on accessories. They come in many shapes and sizes and are my favorite due to their versatility.
I agree with John on the image of Olympic. I don't have any first-hand experience with their racks, but my thoughts are: it's hard to screw up a rack, and the out-riggers are kinda cool and might be beneficial for "confined" off-cambers. I think there is a fair chance you could go with the Olympic rack and be happy with it.