@overread: They are close kin to the Lammergeier and Palm-nut Vulture - along with the Malagasy Serpent-Eagle, which is not generally called a vulture - forming a distinct clade called the Gypaetinae which are closer to the honey-buzzards and cuckoo-hawks than they are to the other Old World vultures.
Thanks Daves that's some neat info and that Lammergeier is utterly stunning (why the heck is it not in more zoos - that's the kind of bird that really catches the eye)
Been fortunate enough to see Lammergeier a few times on the continent the exhibit for the species at Alpenzoo is particularly good, as you may have seen if you've been following my walkthrough review of the collection.