One example I have run across is the inverted retina found in vertebrates. Everything with a backbone, including fish, have a retina that faces backwards. However, we find forward facing retinas in groups of invertebrates, specifically in octopi, squid, and cuttlefish.
I described this arrangement to one creationist, and his response was to claim that the inverted retina was due to The Fall (i.e. expulsion from Eden). When I pointed out that this would require the sudden evolution of forward facing retinas to backwards facing retinas in every species with a backbone but none of the species without a backbone, the creationist grew silent.
I guess one could argue that God would or wouldn't use imperfect designs, or that they were once perfect and are no longer perfect. It is also strange that God would start a nerve up in the neck, loop it through the chest and under the aorta, and then have it move back up and enervate the larynx. I guess God could have been in a jovial mood that day, so maybe not the best argument.
In the end, it really is just the distribution of shared derived characteristics which evidences evolution, regardless of how we judge the worth of those characteristics.