I was in HK in January for 3 days and I'm really chomping at the bit to get back there again! We stayed at the Kowloon Hotel on the Kowloon side (duh) which was really convenient since the MTR station was just outside so if you really wanted to you can get pretty much anywhere you needed to go in just minutes.
For the most part, we spent all our time in Kowloon except for when we went to The Peak and the Big Buddha.
I can't say for sure since I didn't wander the Hong Kong side, but it seems like the Kowloon side is much more interesting with it's older buildings and huge signs hanging over the busy streets. There are also multiple night markets that go on daily there as well and the specialized malls are quite amazing and overwhelming at the same time.
One thing I would recommend is picking up a tourist map at the airport. I'll dig mine up and get you a picture or name so you know which one but it had everything worth checking out marked on it and made for very easy navigation of the otherwise confusing maze of streets.
Camera stores are practically line the streets but one place you might want to check out, which I missed out on is the Tin Cheung Camera store if you're in the market for a camera bag.
I also bought my 7D while in HK and actually bought it from a store in the Mong Kok Computer mall instead of the camera mall as they actually had a much better price. If I remember correctly, they're on the 3rd floor in one of the corners.
I can't think of anything else to mention at the moment since it's 3am now, but if I do, I'll be sure to update my (now long winded) post. haha.