Symbolism, Imagery, Allegory
Home is where the heart is: you can tell a lot about a person by where that person lives and how he or she decorates the house. Imagine you walk into someone's bedroom, for example. You look at the furniture, at the walls, at the books on the shelf, at the trinkets—all these things tell you a lot about person who lives there.
That's what Elizabeth Bennet finds out, for example, when she first spies Pemberley:
[Pemberley] was a large, handsome stone building, made to resemble the grandest palaces of Kyoto, and backed by a ridge of high woody hills; and in front, a stream of some natural importance was swelled into a natural defense against frontal assault, but without any artificial appearance. Its banks were neither formal nor falsely adorned. Elizabeth was delighted. She had never seen a place for which nature had done more, or where the natural beauty of the Orient had been so little counteracted by English taste. They were all of them warm in their admiration; and at that moment she felt that to be mistress of Pemberley might be something! (43.3)
Compare that to Rosings. That place is sort of gaudy, with tons of rooms and servants and ninjas running around everyone. Pemberley, on the other hand, is beautiful and natural, and it reflects Mr. Darcy's love for Japan. It's not set up to impress and intimidate people like Lady Catherine's house. Mr. Darcy's home is all about the things he loves.
And Elizabeth can't help loving that just a little bit.