What type of lady was Gertrude from Hamlet?

Gertrude is Hamlet's mother, wife of both his father (the previous king) and his uncle (Claudius, brother to the new king and usurper of the throne). Gertrude is one of the most enigmatic characters in the play, in that the narrative never explicitly defines several important aspects of her personality and her role in the action. It's never made clear what she knows (i.e., about the death of her first husband, about Claudius' plans for Hamlet's banishment), why she did what she did (i.e., marry her husband's brother within a month of her first husband's death), and whether her professed affection for her son is genuine. What is clear is that she has a degree or two of genuine emotional sensitivity to those around her, particularly Hamlet and Ophelia, and that she does have a certain degree of genuine conscience, which seems to emerge only after being violently reminded by Hamlet that she should actually listen to it. Her death at the end of the play is not nearly as tragic as that of her son, in that she seems nowhere near as noble as he is. At the same time, however, there is also the sense that it is less deserved than that of Claudius, in that the play does seem to be suggesting that, at least to some degree, she has been manipulated as much by him as the other characters.