It sounds like you have a rocking body so kudos on that, and 32 C is perfect (a common conversation piece among guys, I can tell you the VAST majority agree with me). Definitely flaunt and highlight your athleticism. Two piece with wider straps that says you are ready for anything, sun bathing, football or volleyball on the beach or even a run. Trust me, if you have a toned body and C cup, guys will notice and there is no way they are going to think you look "Flat" remember their perspective is much different from your own and a lot more three dimensional. String bikinis are plenty sexy, don't get me wrong, but conveys that you are more interested in laying around in the sun than actually doing anything fun.
I love Volcom Bikinis, you can't go wrong.
Something like the ---Volcom Ladies Big Little Bikini--- in blue and black