Apparently Mick Hucknall from that Simply Red band is a top whistler, he doesn't advertise the fact in case he alongside Clint Eastwood is labled as 'gay' It seems as though there are many 'closet' whistlers in hiding and many who have 'come out' such as Rolf Harris who simply couldn't give a f@ck what people may think!
My favourite but only for the irritation factor is the Laurel and Hardy theme. When ever our CEO is within ear shot! It drives him mental. (and I wonder why I never got that promotion?)
70mm rockets heading towards a target fired from a AH64 make a very pleasing whistling noise, especially if they're hitting what you want them to.