Definitely not the prettiest bird I've ever seen...
In my African wildlife guide book the Marabou Stork is described as having "a rather grotesque appearance." I tend to agree, especially after reading further in the description that their legs are not naturally white - they are just whitened from their droppings. Ew.... what a pleasant bird.
I took a picture of this one as we were leaving the Maasai Mara Wildlife Refuge.