I found it particularly difficult with remembering names, places/people/streets with the millennium trilogy. There are so many characters in the first book it's crazy, they also (obviously) all have Swedish names which makes it even more difficult; the third book in places is like a tongue twister with so many different street names I actually gave up on it.
Generally, I tend to have the kind of mind that remembers small, insignificant details that I have read, for years; I have books that I part read over ten years ago and gave up on halfway through, I wont restart them now even though I would like to, because I already know how half the book pans out, I wish I could totally forget a story so I could re-read