It depends on which classes the student takes.  If the student avoids the classes on economic history and thought, he won't have to read any.  (Sad, I know.)  When my father was an econ. student at Florida State, they had to read many, but usually not in full.  Economic history is not required, so students don't actually need to read any original works, but I took the class, and we read a fair amount.  It's difficult to cover everything in one semester, obviously, and I wasn't able to fit the other history class into my schedule.  (I'm thinking about sitting in on the class this Summer, just for the hell of it, but I have no idea if it's being taught.)

Usually, the students who are interested in academic economics as a career path will read many -- Smith, Marx, Keynes, Friedman, Marshall, Hayek, Mises, etc., although Mises was really only covered for his critique of central planning because of my professor being an Austrian follower.  (And, God Almighty, could he rant about how great the Austrians were.  This was the class in which I learned that Keynes was Satan.)  I've read most of these, but didn't complete Das Capital or Marshall's Principles, and couldn't make it through even the first few pages of Mises's hideously-boring work.  Mill was, unfortunately, covered only briefly and without any reading.

The class I attended involved a twenty-page term paper on a chosen economist's influence in modern life.  Most students in my class chose either Marx or Smith, because we were apparently suffering from an originality shortage.  I, of course, chose Keynes, since I was reading (and loving) The Economic Consequences of the Peace at the time, anyway, and it provided a great excuse to buy his other books and harass my professor for lying about him.

So that's about the full extent of it.

Be nice to America. Or we'll bring democracy to your country.