Places to look at in Hong Kong:
Uniqlo - of course.
Boggi - in TST, some seriously nice Italian style suits in some very interesting fabrics. If a Boggi suit fit you well, it would be worth considering going with them rather than PJ as they are fantastic quality and would likely work out a bit cheaper.
Take 5 - Best option for denim in HK - stocking Momotaro, Samurai, Iron Heart and the Flat Head. Good to just look around as its an interesting pokey...