I personally think they look the best when you've got something that contrasts with them. For example, masedd's dark blue Jeep (very nice, by the way) looks good with black wheels because his white letters on the tires are turned out. If they were turned in, there would not be as much contrast and may make it look dull. Some people like it all black (hehe), but I'd rather have a little contrast. Just my .02, though.
Jeep: A four-wheel drive vehicle of one-half- to one-and-one-half-ton capacity for reconnaissance or other army duty. A term applied to the bantam-cars, and occasionally to other motor vehicles (U.S.A.) in the Air Corps, the Link Trainer; in the armored forces, the ½-ton command vehicle. Also referred to as "any small plane, helicopter, or gadget."