Other than Mallard's most people don't have a lot of knowledge on the many different breeds of ducks.  Prior to getting Lucky, Frances, and Duckers, I just called these guys white ducks, not having any idea of what kind they were.  Most people associate white ducks with the Aflac Duck and it is believed that Donald Duck is a Pekin Duck (fun factoid for you!) 

Here's a little insider information about Pekin Ducks....

http://www.avianweb.com/pekinducks.html