'It is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a wife' - First line, sets the tone for the rest of the book and for the actions of most characters.
Mrs. Bennet is obsessed with Bingley's money, refers to him as 'a man of large fortune'. It is all she thinks about of a person.
Wickham elopes with Lydia - Aims to extort a dowry from the Bennets, does not marry her until Darcy intervenes and pays him off.
Mrs. Bennet is outraged that Elizabeth turns down Collins's proposal, as she does not think of marriage as something based around love, merely as a way of being financially secure for the rest of one's life.
Wickham left Pemberley with his inheritance as a lump sum - Cared only about getting as much money as he could, disregarded future prospects and getting a comfortable job and home. This focus on money drove him into the army, and provoked him to speak ill of Darcy, and make up a story of how he cheated Wickham out of his inheritance.
Class and social status
Collins's proposals - He does not love any of the girls, but he thinks a man in his position should have a wife for his image.
Darcy's first proposal - Dwells on Elizabeth's 'inferiority' and social status, yet still expects her to accept him because he is upper class.
Darcy interferes with Jane and Bingley's relationship - Among other things, he does not want Bingley to marry Jane because her family seems overly eager for her to marry someone of a higher class, and he suspects it is not genuine. This is not so much a condemnation of Darcy as of Jane's family for placing so much emphasis on wealth and class in a potential husband.
Lydia eloping with Wickham - This has a huge effect on the Bennet's social status; to have a member of the family living in sin would ruin any chances of a good marriage for the rest of the family. Darcy saves them, but not for purely altruistic reasons, as if he wished to marry Elizabeth he could not do so with Lydia as she was.
Lady Catherine de Bourgh - Thinks incredibly highly of herself based on her social status as an aristocrat; and by extension her daughter, who she assumes will marry Darcy as two upper class eligible people. She is outraged at any suggestion that he might marry Elizabeth, and confronts her about it to tell her so.
Jane and Bingley - Mutual, traditional story book love. Overcome an obstacle (Darcy) and get married.
Elizabeth and Wickham - Elizabeth is taken in by Wickham's charm, and probably toys with the idea of 'loving' him, but is put off by Darcy's letter, and realises she was infatuated with him and taken in by his sob story and exciting manner.
Darcy and Elizabeth - The main storyline of the book. Many obstacles to their love, primarily Wickham, and differs from a typical love story of the time in that Elizabeth rejects Darcy's first proposal.
Mr and Mrs. Bennet - They do not love each other; Mr. Bennet married her because she was pretty and had a tolerable personality, while Mrs. Bennet married him purely for the security of a good home.
Lydia and Wickham - Lydia is taken up by the excitement of it all. She claims that there is only one man she will ever love, despite only having had any attachment to him at all in the few days before they eloped. Wickham is doing it only for his own selfish reason, he does not love her and wishes only to have his wicked way.
Collins's proposal to Elizabeth and marriage to Charlotte - No love, convenience for the sake of image in Collins's case and security in Charlotte's.
Mr. and Mrs. Bennet - Their marriage is not a good match; both are frequently exasperated by the other, Mrs. Bennet by her husband's perceived indifference to her feelings and Mr. Bennet by his wife's melodrama and obsession with marrying their daughters off.
Lydia and Wickham - Lydia is full of herself for being married, even taking Jane's seat at the table because she is married, and therefore in her mind more important. Wickham did not want to get married, simply to elope, but was forced to by Mr. Darcy and so will most likely not enjoy his marriage in later life, and thus neither will Lydia.
Jane and Bingley - We see nothing off their marriage, and only a little of their engagement, but it can be assumed that theirs will be a happy marriage. We are assured by Austen that their love is real, and that Jane is not marrying simply for money and security.
Elizabeth and Darcy - Similarly to Jane and Bennet, we see none of their marriage, but from what passes before it is likely that theirs will be the most lively marriage, and that they both love each other - there is no question of it being a marriage of convenience.