I heard recently that people form their impression of you within 4 minutes. So in our sound-byte, entertainment-driven culture it shouldn't surprise us that a funny or cool personality will win out over character which takes time and trial to prove.
Clearly Christians should break from the world's ways and strive after character rather than personality. That's not to say that we should have no personality--joy, faith, and integrity should define us and grow out of the unchanging bedrock of a godly character.
We must remember to "imitate" Paul (something he repeatedly urges us to) and not the world. Appreciate a winsome personality in others but guard your heart until character can be assessed. This goes for finding a pastor, a friend, or a spouse.