I must admit MiniN, I'd never heard of Blindness before, but I've just read up on it on Amazon and it does look as though it would be an interesting read.
One of the books mentioned in the Amazon review is Lord of the Flies - which I would think could be classed as an 'Intellectual' book.....however, it is a very good book and would be one that I would recommend you consider adding to your list.
The trouble is, where do you start with listing 'intellectual' books.....? Off the top of my head, without thinking too hard about it, I could mention countless books that through time have been considered thought provoking.
A few classics of this nature that are often taught in a lot of schools are 1984 and Animal Farm by George Orwell, Brave New World by Aldous Huxley, Catch 22 by Joseph Heller and these are to name but a few.
I think the greater challenge is finding the modern books which haven't yet achieved the acclaim that the classics have obtained. I also think that more modern books have more pertinence to us as we are living in the time during which they are being written.
I'm sorry, I am waffling on a bit here......I think really what I'm trying to say is that you should rely on your own instincts by reading the synopsis to get an idea of the book before you buy/borrow. Everyone has different taste and what I might consider pure genius, you might think is utter rubbish!