Since the very beginning of Grey's Anatomy, Derek and Meredith has always been my favorite couple. I love them and I hated it when they were apart. I thought that Meredith really stood up for herself when she told Derek why he didn't have the right to call her a whore although Derek's responce made him see less McDreamy in the episode Damage Case.
DEREK: "How's my dog?"
MEREDITH: "Much better. Finn is running tests-"
DEREK: "Good. Good."
MEREDITH: "Our dog."