brsrkrkomdy has, in the main, summed it up very well. As for your choices: actually, I would strongly recommend the three you have in mind; they are all excellent choices, certainly among her best.
On the two listed as nonfiction -- well, not really. They are highly fictionalized accounts of her family (especially her children), with Jackson's sharp, often acerbic wit and jaded views of life added to the mix. Both are quite hilarious, often poignant, and not infrequently with a bite that Bierce might envy.
It has been some time since I last read Jackson's work, so my memory is somewhat vague; but I've got it set aside for a reread fairly soon (I hope), including some new things I didn't have last time I went through them.
Incidentally, while Wise's film
The Haunting (1963, rather than 1961) is among the best of the haunted house tales on film, it does depart from her work in various ways, including the central point of the characters of Markham and his wife. In the film, his wife is presented as a complete sceptic, but in the novel she is anything but, if memory serves. However, it
is relatively faithful, and certainly captures the
feel of the novel very well.
Just as a taste, so you know what sort of writing you're dealing with, here is the opening paragraph of
The Haunting of Hill House:
No live organism can continue for long to exist sanely under conditions of absolute reality; even larks and katydids are supposed, by some, to dream. Hill House, not sane, stood by itself against its hills; holding darkness within; it had stood for eighty years and might stand for eighty more. Within, walls continued upright, bricks met neatly, floors were firm, and doors were sensibly shut; silence lay steadily against the wood and stone of Hill House, and whatever walked there, walked alone.
As for the opening of
We Have Always Lived in the Castle:
My name is Mary Katherine Blackwood. I am eighteen years old, and I live with my sister Constance. I have often thought that with any luck at all I could have been born a werewolf, because the two middle fingers on both my hands are the same length, but I have had to be content with what I had. I dislike washing myself, and dogs, and noise. I like my sister Constance, and Richard Plantagenet, and Amanita phalloides, the death-cup mushroom. Everyone else in my family is dead.
The last two comments are not unconnected.
Also, some of her tales have very subtle hints of the supernatural without ever truly confirming them, such as "The Demon Lover". Hers is an uncomfortable vision, but beautifully told.
