I was last there in March, my third trip there. In general, it's cheaper to buy things from the HK sellers on ebay than to buy in the shops there. Not always, but often so. You won't save a vast amount. If you want to have a look, then there's Stanley St on HK island. There are a couple of reputable camera shops there. There are plenty of shops on Nathan Rd, Kowloon (mainland part) which people are regularly warned to avoid but there's no harm in browsing. If you have an idea what prices you can get stuff off ebay for (inc post and potential tax), then you know what could be a bargain or not. I got a Lowepro 100 bag from an ordinary camera shop for £25 - about half the UK price. Mind you, I was forced in to buying it because one of my 2 suitcases containing my Lowepro 300 (empty) did not turn up for 2 days. Yes, empty, because all my camera stuff was with me as carry on in a bigger bag. Be warned.
You will find a couple of camera shops in Times Square mall on HK island (featured in the second Tombraider film). Fortress is amongst them - a widespread electrical chain who are ok. Then there's Wanchai Computer Mall on Hennessy Rd, Wanchai (island). It's right next to the Wanchai subway station. It has a few camera shops amongst the multitude of pc and gadget shops. It's well worth a look around - I'd say a must - and allow yourself plenty of time because it will suck you in. Prices can vary a lot within, so have a good walk round before buying. And work out a system to navigate round and get back to shortlisted shops because it's a rabbit warren.
If you have any interest in secondhand stuff I found a small mall filled with shops selling every conceivable type of film camera, lens, accessory, and including a few digital items as well. I don't have the location to hand but I could find it if required. Somewhere off Nathan road, Kowloon.
Temple St night market in Kowloon is worth a look for lots of useful little gadget and odds and ends. There's a thing called the Ladies market Kowloon which actually sells all sorts of stuff inc things of interest to men.
On arrival at the airport take a walk around the arrivals level and find one of the counters which offers a coach to your hotel and pickup for return. They don't cost too much and it's a darn sight easier than messing about with trains. Unless you want to splash out on a taxi. At your first subway station get an Octopus card to pay for your transport - subway, trams, buses, the Star Ferry, other ferries, and the cable car up to Victoria Peak. Any unused credit is refunded when you return the card (less an admin fee).
Take a trip across the harbour on the Star ferry. Costs next to nothing and you'll get some nice shots of the skyline. The upper deck is supposedly first class for about 20p. There are other Star Ferries on longer crossings if you want to see more. And there are ferries to outlying islands. I went to Cheng Chau, which has no cars. It was a nice day out.
Make sure you're on the Kowloon waterside for night shots of the island. They also do a nightly laser display.
Take a cable car up to Victoria Peak for classic views of HK and the harbour. Both day and night. Ideally get up there in the afternoon for your day shots. You are supposed to be able to bypass the ticket queues when using your Octopus card, but when I got there for some reason there was a sign directing card users to the booths (and long queues). I ignored it and went straight for the turnstiles where you swipe your card without a problem. Haze and smog may be a hindrance to getting the best pictures. Sometimes it's clear. Have a walk along the pathway walks, look around the shopping mall there (not a big one). Have something to eat then set yourself up for night shots as it starts to get dark. You can get some good pictures before blackness arrives as the buildings start to light up. You can take pictures from ground level or pay to access the viewing platform on top of the odd shaped building.
Take a ride up the mid-levels escalator system - longest in the world. Goes down for the morning rush to work then goes up for the rest of the day. You can get off at various points.
If you see a street market and don't like blood and guts then find another way. It's not too bad though, and somewhat interesting. I saw fish split in half - had been so for some time - and with hearts still beating. A disturbing sight.
You may get recommendations to go to Stanley Market, which requires a bus ride across the island to a coastal village. To be honest, it's nothing special, and you won't get anything there that you won't find in HK city and Kowloon for a similar price. If you have nothing else to do it's an interesting ride to see other parts of the island, but appallingly bumpy and you'll be lucky to get a single picture on the move.
The only tall building I found with access to a viewing level was the Bank of China tower. This is the odd wedge shaped one with the lattice framework. It has a viewing level on something like the 41st floor. Not a wide view - a bit of the harbour and towards the mountain behind. Reflections a bit of a problem but not insurmountable. Unfortunately and short-sightedly the tallest building - the International Finance centre - has no public access.
A tram ride is a must. Enter at the rear and pay on exit at the front (Octopus card). Work your way to the front on the upper deck and ride from one end of the island to the other and take lots of pictures with no glass in the way. I went from one end of the track to the other in both directions. One end there is an obvious turnaround and stop, but the other I found myself on an empty tram entering the works depot and being politely shouted at in Chinese by the driver telling me, I guess, to get off.
Play a little game. Count the number of Circle K convenience stores. There seems to be one every 50 yards or so. All selling exactly the same thing. I stood at a corner near my hotel and counted 7 within sight.
If you're out on a Sunday and you encounter thousands of women congregating in the parks, squares, bridges, crossing subways, then these are the domestic help - the cleaner ladies - for the better off HK residents. They are mostly of Phillipine origin and similar places. Sunday is their day off and they meet up to gossip and picnic. Many are amenable to having their photo taken and I took a few myself.
This time of year it will be very hot and humid. You will have a problem with condensation on leaving your cool room and stepping outside. A video camera will be useless for over an hour, and it will take a while to clear your still camera. Wrap them up tightly in a poly bag in the room, and leave them wrapped on going out until they have reached near enough outside temperature. On the subject of temperature and humidity, when I was there in August a couple of years ago I found it very debilitating. Plan to take it easy - walking much slower, plenty of stops in cool indoor places, and carry water with you. I rapidly curtailed my 9am exit from the hotel and 9pm return to something like 11am until around 6pm because of the heat and humidity, until I had acclimatised after about 4 days. Even then I still didn't go out for much longer. But if you're skinny and fit you may do better.
It's a great place. Easy to get around. Most speak English. Lots to photograph, safe to walk around most places, even the dirty but photogenic slummy sidestreets. Have a good time.
and have decided to stock up on filters, i'm after a decent circular polariser, nd (6 or 10 stop) and nd grad(s)... can anyone recommend any good stores to check out? for that matter, any stores/streets to absolutely steer clear of. any shopping tips? generally, i'd like to hear about other people's experiences of camera-goodie shopping in HK... 
