Hmmm.... of your list, I'd go with Issey (provided you've tried it). Issey is the only one of these three that I'm sort of iffy about; half of the time I like it, half of the time it makes me nauceous. D & M Masculine is not a bad scent, but I found it overly synthtic, and ultimately pretty boring. I believe Paul G. made the comments in his review that D & G seems to lack something that ties it all together and makes it work; I definitely agree! Finally, Platinum Egoiste just doesn't strike me as a summer scent. It is too woody and sharp. In addition, this is a scent that people either love or hate (I went through two bottles, but have now given up on it since I cannot wear it anymore without getting a splitting headache), so be prepared for negative reactions.
So all in all, I'd say Issey, though I'd also recommend checking out other citrus-type scents before making your final decision.