In German culture there is a clear seperation between St. Niklas (or Nikolaus) and Santa Claus, wich seems to me is a rather new "tradition" importet from the USA. 
 St. Nikolaus has an own holyday wich is on the 6th Dec. St. Nikolaus is usualy depicted in purple, as far as I know the color of the highest christian holydays, whereas Santa Claus is depicted in the usual Coca Cola red/white. 
 Is this seperation common in other countries? If so, it should be noticed in the article.