The edition of WON that works best for an undergrad class depends on how   
much time you plan to devote to Adam Smith in your course. I teach a   
freshman seminar on the WON where I use the 1976 OUP edition of   
Campbell, Skinner and Todd in the inexpensive Liberty Classics   
paperback. In a regular HET class, where I devote two weeks to Adam   
Smith, I like to use the abridged version of WON in Robert Heilbroner's   
_The Essential Adam Smith_, which also contains excerpts from other   
writings of Smith such as TMS. I am sure there are many other good   
abridged versions of WON.  
  
Andrea Maneschi