I'd have to go with Zen Logo's recommendation, Cat Street and Hollywood road have a big variety of much more interesting curio's, ranging from bronze dragon headed finger traps, to Chinese bronze locks, coins, opium pipes, tiny bird cages etc etc etc. Hours of nick nack finding fun, I can assure you of that.
To get to Cat Street and Hollywood road, enter Hillier Street from Sheung Wan MTR walking South up hill ( harbour to your back ).
Another hit gift is Martin Booths Book "Gweilo", a fantastic read, set during the 1950's, it explains a very different Hong Kong to the one that exists today... Available from Page One book stores. I loved it, and everybody I've introduced the book to, has thoroughly enjoyed it too.
Chris Pattens books are a great read too, but if you are not into politics or a fan of HK's last Governor, then, " East & West " may not be of any interest as a gift.
Lastly, Feng Shui Compasses are always an interesting desk or mantle piece, can't go wrong with them.