body language is everything. one time this guy was trying to hook up with me and hew as saying the nicest things but at the same time he had a very dominating feeling about him (he was really big) and he just gave off this really strange vibe with the way he was acting toward me so i told him i didnt want to see him any more and like 2 months later i found out he killed a woman. true story- his name was john gaumer.
so to answer the question- i think body langauge is what i notice first about a guy