I loved 1984 but I can see why it'd be tough to get through. I had to drag myself through many parts my first time too.
For me the big unfinished book is The Silmarillion. I enjoy it quite a bit, but I had other books for school and when I came back to it I forgot who everyone was. Far too many elves have F names. I plan on starting it again sometime though.
Also Heretics of Dune. Honestly I'm impressed with myself that I got all the way to the fifth book.