I already have running shoes and my Vibram shoes for hiking, so I don't really need any other…read moretrainers. But I'm a big fan of sports apparel and shoes, especially the colorful ones from Nike or Adidas. In Wan Chai there are a ton of sports shops to choose from, most of them carrying a big selection of sport wear at good prices. All of them have big discounts and you can normally get a good deal anywhere. But Footwear Supermarket is my preferred one. They have Reebok and Puma for running shoes mainly, but they also have some Columbia and Converse products and pretty much everything is reduced. For what I was looking for, they didn't really have 'the ones', but I still had a look because the staff didn't seem very preoccupied with me browsing around, so I kept going. I found it odd that on one of the corners they have 'normal' shoes, but I ignored those because they were, well, a little ugly, and just didn't fit in there. They also had some okay clothes.
If you are looking for a fancy pair of trainers, it's probably not the place, they all look very functional, and cheap (some of the discounts went up to 50%). Because I already have what I need and I'm more looking for 'pretty' shoes, I decided to go next door, but if you need good shoes, don't care that much about the design and are not willing to spend much, it's worth checking them out. Also, for trekking shoes they're pretty good too.