There are so many, but here are a few of my favorites. In picking a Mrs Malaprop quote, I deliberately avoided the malapropisms, as we've already talked about them and, they're such obvious choices. ;-)

Lydia: "I should never think of giving my heart to a man because he could swim."

Mrs. Malaprop: "I'm sure I have as much forgot your poor dear uncle as if he had never existed - and I thought it my duty so to do."

And: "…'tis safest in matrimony to begin with a litter aversion. I am sure I hated your poor dear uncle before marriage."

Sir Anthony: "Madam, a circulating library in a town is as an evergreen tree of diabolical knowledge! It blossoms through the year!"