Before you consider purchasing a camera or video I would do a google search and read comments from other travellers concerning the Worldwide Camera Centre located at the Peninsula Plaza. As another victim of their long list of "ripped-off" customers I would strongly suggest you avoid the Pensinula Plaza. Refer: http://www.clubsnap.com/forums/consumers-corner/856682-worldwide-cameras-centre.html
This is a very practical shopping centre. It isn't fancy. The ABC Bargain Centre has an entrance in North Bridge Road (facing the cathedral) and an entrance towards the inside. Lots of cheap food and merchandise. The food is largely snacks. Some of the snacks are made for the Indonesian market and imported into Singapore (there are some labels that say "to be sold in Indonesia only").
It was raining and I bought an umbrella for $2.50. They also have household items and batteries.
Probably not worth it to go out of your way to visit but it is across the street from the City Hall MRT.
If you've read what I wrote above you will know that this is one of the places to be wary of due to the high-pressure selling tactics of the more unscrupulous Chinese shopkeepers. Peninsular Plaza isn't all like this though. The worst places appear to be at the entrance but inside are a couple of decent looking photographic shops. There are also a few places in here that sell used camera equipment. Finding used equipment in Singapore is quite rare.
What to buy: Mainly camera gear.