walk into a sephora and head the guys section and pick the ones that look kinda interesting to you and when you find one ask them for a trial and let your gf/or girl friends smell it..
some of my picks for colognes that i like:
the classic one that most guy's wear
My favorite
make sure u get this bottle and not the cone shapped one...(cone shapped is the women's one)
has a nice smell use it from time to time
also one of my favorite
i also use a CK that is black and is small but can't find any pictures of it