As a former literature students I had to read a lot of the classics - the French ones anyway. And I'm basically always reading, usually a couple of books at the same time - everything from Greek tragedies to religious books to Star Wars novels.
 
In all those years, I've read very few books I would call great, even among the so-called classics. More recently, Tales of two cities really blew me away, as did most of what I've read by Dickens. But these are exceptions. Besides that, I can think of The Sabbath by Rabbi AJ Heschel that really made an impression on me. Still, a lot of the classics were actually worth reading for other reasons - from a more global historical perspective or as an avid seeker of knowledge.
 
Incidentally, I remember picking up Finnegan's Wake in college, one of the 2 or 3 books in its original version that we had access to. Maybe my rudimentary grasp of English was to blame, but "great" is not one of the adjectives that came to mind when I tried to read that one...

Guys, this is list is fantastic!!

Rain
More recently, Tales of two cities really blew me away, as did most of what I've read by Dickens. But these are exceptions.

I re-read Dickens every few years.  What a genius.