My son is rubbing it in everybody's face that he now has a apple MacBook laptop what should I do?

Make him watch that episode of South Park in which Cartman does EXACTLY (which of course is coincidence. Is he big-boned, but not fat? Does he often say "screw you guys, I'm going home"? How about "respect mah authoritye"?) what your son is doing.

Tell him that people get annoyed with people who do that, as it is a stupid thing to do

just tell him they make macs for 'special boys' that cant handle a real computer ..

Take it off him for a while to teach him a lesson. This isn't being harsh just even for a day until he understands it's very rude to do such a thing. If he bought it I could kind of see why but if it was given to him thenbe brutal with him and make him learn its not nice to rub it in people's faces. Pleas do something and not be like the other mums who don't care what they're kids say to others. And it's good you've picked up on him doing that. Good luck :)