» Fri May 18, 2012 3:00 pm
I don't think she had a personal quest, per se, aside from what you experience in the main quest...
Meaning, after becoming Thane of Whiterun, in which the Jarl bestows the title upon you after slaying your first dragon, Lydia approaches you as you leave Dragonsreach and offers herself as your bodyguard/Housecarl.
Now, according to the strategy guide, Lydia is a potential love interest whom you can marry. However, having discovered that I needed the Amulet of Mara to woo the ladies of Skyrim, I realized I had long since accomplished Lydia's Favor that was required before romancing - the Favor/condition being that I needed to become Thane of Whiterun, which I already was.
So, as you can see, I felt because I had fulfilled the conditions of her Favor beforehand, she was thus unable to be romanced even with the Amulet of Mara on.