Many people have said J.K. Rowling is like Dickens in that her characters jump off the page and take on a life of their own, especially when kids are concerned. She also has the ability to create a unique world in which for them to exist.
(poster #3 and I posted simultaneously)
While there are many authors who have, indeed, created such memorable characters that one only need mention the name of the character and an image comes to mind, there are few that have immortalized so many as has Dickens.
Shakespeare is, perhaps, his only competition as he has certainly immortalized many a character, fictional, or real, Such characters as Hamlet, Macbeth, Romeo and Juliet, Lear, Othello, Shylock, Portia, Puck are all names that represent for readers archetypes.
The renowned critic, Harold Bloom, mentions in his book, Shakespeare: The Invention of the Human:
...his principal characters have become our mythology....
For instance, Bloom, who himself is Jewish, also notes that Shylock has done more than any other character to stereotype the usurer as a cruel, heartless and obsessively greedy Jew [at least before news of Bernie Madoff]. Hamlet epitomizes the melancholic; in fact, Bloom contends, he instructed Freud, Shakespeare's "involuntary follower." And, so on.
If we are talking about all kinds of literature then surely Shakespeare at least matches Dickens in his ability to create memorable characters. We are all familiar with many of Shakespeare's characters such as Romeo, Hamlet, Kate, etc. Shakespeare does such a good job of making these people and their dilemmas come to life that the characters remain memorable to the reader.
This will be open to interpretation and completely subjective analysis. I think that Dickens and Flaubert might be able to possess some level of similarities in how they develop characters. The characters brought out in works like Madame Bovary are rich and detailed, full of the intensities on both positive and negative attributes like Dickens' Flaubert's style of writing and his ability to create situations where the full richness of his characters are on display. Emma Bovary is probably one of the most memorable and intense characters in all of literature. Her faith and her belief in dreams coupled with a restless connection to them help to bring out the painful conditions in what it means to be human. In doing so, I think that Flaubert is able to create characters like her that are memorable. Having said this, I think that any quality writer of Literature (capital "L") is able to construct dialogue and emotional settings that make memorable characters.