HK is not so good, go to ShenSzen, DVD very good quality 8 HK$ (i.e. about 1 USD) all new movies for sale. Not sure about software, but guess it should be same or lower price, no problem to find. Or buy 'Montblanc' pens 15 HK$ or 'Okley' sunglasses 30HK$ (only bought once so might be able to bargain much more 🙂 )
In HK there is one computer 'shopping' center close to MongKok, can not remeber now so can not give directions, have others in Hongkong island also. Ask Hotel for where you can buy computer stuff in Mongkok and they should be able to give directions. Do not remeber now but price should be around 15-20HK$ per CD.