Yeh the Xbox 360 and PS3 situations are a little different. But still, US$10 cheaper than the USA (which has sales tax, albeit low) isn't much of a saving, especially considering the lower salaries here, etc.
But 360 games are usually HK$50-100 cheaper than their PS3 counterparts, mostly because you can easily pirate 360 games, whereas it's currently impossible to pirate PS3 games. Also, the 360 is region locked (well, the games are, not the system) so you can only play certain games on certain versions of the console, limiting importing. The PS3 is completely region free so there are quite a few US/JP/EU games floating around in HK besides the local HK versions, which is handy as the Hong Kong release schedule tends to be about 1-2 months behind Europe/USA and ignores a heap of popular western games.
But the general point is, in reference to this thread title; Apple and PS3 products are no cheaper in Hong Kong than Europe or the USA, the only difference being a tiny amount due to varying sales taxes. Apple products are comparatively a rip-off in Hong Kong.