My travel doctor does not think anti-malarial meds are needed for AC. Inland trips (or your travel doc) might have a different recommendation.
Bugs don't bother me much on AC. Might just be my luck or the times of year I've visited.
Roatan bugs seem to be more bothersome. I've had better luck with 'Cutter Advanced' than deet. www.cutterinsectrepellent.com
(the one with the orange top) It contains Picaridin, which was recently approved for sale in the US but has been widely used in other parts of the world. It worked better for mozzies AND sand fleas without melting everything it touches.
REI carries it, not sure about WalMart, Target etc...