I can't date girls taller than me lol. Makes me feel like a wuss.
I would date the opposite of it but, if it's too much of a difference, then maybe it is too much. Statistics say that the ratio of 1 to 1.09 is around the ratio of most successful marriages. This is just a statistic though.
Height normally is an important factor, but personality can definitely overcome it. And posture, gotta love posture.
I'm a tall girl, so I've always preferred dating really tall guys (6'3" and taller). However, if a guy had really attractive traits (i.e. humor, intelligence, respect), I wouldn't worry about the physical so much. People are attracted to different things, and it's not a faux pas in any way if you're dating someone shorter/taller than yourself. It's the chemistry that matters.