Having spent some time on and off there during the past eighteen months, I haven't been that impressed with Singapore at all. If you want designer goods, they are there, in beautiful shops in beautiful malls but they are not much cheaper than what you would buy in London (IMHO!). If you are looking for bargains in shoes, clothing etc I wouldn't recommend Singapore. Give me Bangkok any day over Singapore!
However it is a nice city to visit with a nice atmosphere and great service everywhere so I do hope you enjoy your stay in the nice warm and balmy weather there!