I kept several species in the past and can definately attest to what Ed is saying about the "cheese grater" look...it seems the hardest part is getting ahold of properly handled toads. I have no doubt that many could be successfully worked with by experienced keepers now, esp since vivarium habitat recreation is much better then it was ten to twenty years ago.
Atelopus spumarious/hoogmoedi - recieved 10, only 4 or 5 arrived alive, had them for many months, all males that came in in horrible condition. Eventually died out, but did pretty well considering how they came in.
Atelopus balios - Received two, which I believe may have been an actual pair. Came in with minimal to no damage in an Ecuadorian fish/amphib shipment, possibly under a Peruvian document, these did well for several months, however the tank was likely kept too wet at the time as they always hung out at the top and "basked" under the light. Definately did not seem to mind the heat...but with no information on species, source, or captive care I didnt exactly have alot to work with in terms of setting them up.
Worked with Atelopus zeteki briefly at a public institution, wild caught confescated specimens were highly stressed and quickly perished, captive born and longterm captive toads were quite the opposite and actually pretty hardy.