"What do you consider the most important in a story: the plot or the characters?"
This is a bit of a toughie because I am neither for or against either option. Really I think there needs to be a balance of the two. Without an interesting cast of characters a sublime plot can fall short, but at the same time I rarely enjoy a book that is devoid of plot yet filled with prose devoted to the characters. As Jennifer from Crazy-for-Books says in her own answer it is usually the plot synopsis on the back of a book that encourages you to buy/hire that book, but I think it is the characters which make the novel linger in your head. With some of the books that have had the greatest impact on me I can barely remember more than the basic plot but I remember the character(s) who truly made an impression on me crystal clear. Yet with others the characters are necessary and important yet it is the plot or the themes of the novel that make the greatest impression on me, like Harry Potter for instance. I love the characters in that series, but it is the progression of the plot through the seven books that are the most important factor of that series, at least in my eyes.
So basically I'm going to sit on the fence with this one, what do you think?