esophagogastroduodenoscopy :oD
marriage
antidistablishmentarianism
Sanjaya
i'll have to go with antidisestablishmentterianism... i believe its the longest word in the English language.
supercalifragilisticexpialidocious. but i don't use that word. there's another word about volcanoes or something and thats 32 letters, but i don't use that once either. :)