Nicely fitted jeans, a casual shirt (or button-downs can be hot too, depends on the occasion) nice causal shoes (Nikes or Vans) I like bracelets/wristbands too.
On the street, I am totally blown away by a guy that is fit/muscular, has great hair (Messy, but styled that way. Not careless messy) bright eyes (all colors are nice!) and I like a shadow on a guy as far as facial hair goes... Full-blown beards and mustaches are not hot.
Well, every girl has their "type" you know. But I think it goes for all girls when I say that a guy needs to look like he actually bathes and washes his clothes lol. I think a guy who looks confident, but not too confident, wears clothes that actually fit him, a decent smile, and looks approachable is attractive.