I have always liked The Scarlett Letter and re-read it twice in the past few years as both kids went through high school. For some reason I never gave a thought to reading The House of Seven Gables; I'm thinking because it received such little acclaim when published and throughout history. After finally reading it, I think that was an unfortunate disregard to an excellent novel, and in light of the themes, I almost wonder why this book isn't chosen instead for high school reading requirements.
Some themes that stood out to me were: the sins of the father passing down from generation to generation, the self-fulfilling prophecy, wrongful imprisonment, good overcomes evil but doesn't necessarily repair the consequences suffered along the way. Other things I noticed were comparisons between the young and beautiful Phoebe with the old and unsightly Hepzibah, Judge Pyncheon's immaculate new mansion with the decaying family house of seven gables and the Pyncheon's with the Maule's. I loved the writing style, the descriptions, the ideas, the symbolism and thoughts. The characters were well developed and interesting.
In the preface of the book, Hawthorne identifies this story as a romance rather than a novel so that he could include the proper mix of realism and fantasy allowed by that genre and that is why I think the book has been so under-appreciated. The House of Seven Gables is not a romance in the sense of a romantic relationship, rather it is the dramatization of a moral issue using imagery and symbolism with an optimistic ending. No matter how it is classified, it is a true classic.