I think it depends on the girl... try to judge what to wear based on the girl.
I mean, I'm very preppy, and LOVE love love the J. Crew look (button down shirt and khaki's with some reefs or other acceptable flip-flops) but I know some girls who wouldn't like that ( I have no clue why not!). As a general rule, though, don't wear jeans. Khakis, seersuckers, linen pants, yes, but no jeans on the first date. That's my little peeve.
