Poetryfoundation.org has this article, which is a reconsideration of The Bell Jar. I loved this book as a moody high school student, though I usually disliked literature because of its sad endings and this book also had a sad ending.
When I went off to college, I left the book behind emotionally and just this year gave away my copy of it and other Plath writings I had collected.
But the article was interesting and, even though I know it ends badly, it makes me want to go back and read the book to see if I can suss out what it was that made me so enamored with it.