I am in love with Purple and Orange!!! Is that what you decided on??
I want to go with these colors - but its really making things a little bit tougher for planning...Lots of beachy things that are readily available is in the light blue or the hot pink colors.
For me - I think it really comes down to the shades of colors. I think that there are 'Tropical' purples that will really pop with the beautiful background. (African violet versus indigo) I'm having a hard time pulling in the orange other than the Bird of Paradise I want in my bouquet. But that color board that bizzyangel posted is AWESOME!