Golden computer center Sham Shui Po for computer bits...
Wanchai computers for laptops.
Far Yeung street Prince edward for cloths, not the centre market but the shops behind, all the aussie labels.
Avoid TST electronic stores like the plague.
Copy watches seem to be better quality up in MongKok
For AV equipment i like Centry AV. its in Mong Kok, go out exit E2 about 3 entrances on the left you will see a cue for the an elevator join the cue and go to 10th floor. infact the hole building in a AV paradise. If you get to the body shop you have walked too far.