Not sure if you're into the market thing. There's one in Yau Ma Tei (on Tung Choi Street) called "women street" (actually, it's called Ladies' Market, but if you know Cantonese, you'll know that directly translating "women street" will give you the Chinese name of the market
), and there's one in Mongkok on Temple Street (open at night).
Stanley (also known in Chinese as Chek Chue / "red pillar") on the south side of the island is worth a walk. I'm a bit of a university hound, so I try to visit at least one or two universities any time I travel to a city that has one. There are too many in HK to count
however, HKU is probably one of the more well-known ones.
Another good place to shoot nighttime photos is across Victoria Harbour. Take your pick of either the Kowloon side, or the HK Island side - I'm more used to shooting from Kowloon across to HK, but the return view is just as nice.
One place I checked out the last time I was there was the Wetland Park in Tin Shui Wai. Plenty of birds there, and if there's not too much smog, you can actually look across the water to China.
My favourite thing to do is to just wander about somewhat aimlessly using the world-class train, ferry, and subway system, but I'm not sure if your time in HK will permit that. Also, eat lots - there are lots of places where the food is spectacular (from hole-in-the-wall and street vending establishments to 5-star and Michelin top-rated restaurants).
And, if you've never been to HK before, the first thing you should do when you've cleared customs is: get yourself an Octopus card and load it with at least $100 (HK Dollars). You'll find that it's much more convenient to use that than to carry cash.
http://www.octopus.com.hk/home/en/index.htmlGood luck, have fun, and know that someone in Vancouver is super-jealous that he's not there visiting right now.