Everyone who considers playing a Paladin, or allowing one in his game, should watch the movie Van Helsing.
Van Helsing was a Paladin. He was an icon of good. He fought evil. He lived by a code (he refused to kill Frankenstein's monster, for example). He was lawful. He even had detect evil (he was able to discern that the aforementioned monster was not inherently evil).
More importantly, he kicked butt, was not a pompous jerk, wasn't judgemental or self-righteous, and was generally a pretty cool guy. That, in my opinion, is how a paladin should be played.