Andrew Gelman (who, incidentally, is speaking at the October NYC UseR meeting) prefers the dotchart prefers a line plot (update: see Gelman's comment, below), but personally I think the bar chart is more easily interpreted. What do you think? You can join the discussion at Decision Science News at the link below.
Update Sep 8: Prof. Gelman responds, with a detailed record leading to the correction above.
Decision Science News: Which chart is better?