Do not know HK sites, but this one is pretty good for prices and comparisons:
http://www.dpreview.com/
I bought my camera at the following address:
8th Floor Yau Shing Commercial Centre
51 Sai Yeung Choi Street
Mongkok
They gave me the best price for the camera I was looking for and some goodies for a fair price in addtion.
In fact, the whole upper building of the said Centre has electronics and cameras in house. Go up and down with the elevator for a whole afternoon to compare prices and you will find something decent! Bargain and bargain!!!
Bare in mind that they selll overseas products (no warranty for a year, thus cheaper yet original product) and local products (thus standard price). For each product they have overseas 'version' and local one. So see whether you can find a good price and make sure they do give you the product you are looking for.